Haven’t gotten around to updating the site, but here’s gallery of images I recently culled…
Now where did I put those…easily finding image files on your Mac
I was recently asked if there is an easy way to find image files on a Mac with little structured file management. In other words, photos stored in many locations, often alongside documents that might or might not directly relate to them.
Here is my attempt at answering the question(s), which seems worth sharing. Please feel free to post any helpful suggestions or observations.
QUESTION: I bought an external hard drive for backing up my files. Can I just plug it in? Is there anything I need to do before copying files?
ANSWER: After connecting your external hard drive to your Mac, the drive’s icon should appear on your desktop. Access the external drive as you would any other drive or folder.
* If you are prompted to format the drive (in some cases, your drive may not have been preformatted), follow the instructions and for Volume Format, be sure to choose “OS Extended/FAT 32”. Chosing “NTFS” or “Mac OS Extended (Journaled)” will make the drive unreadable by either Windows or Mac machines.
Personally, I would choose a meaningful name for the drive. Something with a dates tamp and name, like 100308matpearson. However, any drive name should be fine (including “untitled”); this can be changed at a later date.
* If you cannot access the drive, I suggest following David Xie’s well illustrated blog entry on formatting external drives with Mac OSX, http://davidtse916.wordpress.com/2007/12/02/how-to-connect-a-new-external-hard-drive-to-your-mac/ .
Before disconnecting an external drive, you will need to “unmount it” by either dragging the drive’s icon from the desktop to the trashcan, or by control clicking (hold down “ctrl key while clicking) on the icon and choosing “eject”.
QUESTION: I have pictures stored throughout my computer; how do find them?
ANSWER: Ideally, your image files/pictures are stored in a structured file system with meaningful (and cross-compatible) file naming and a collection of appropriate sub folders. I use a parent/child (sub) folder scheme where the parent folder is named “images” and the sub folders are named with date stamp, underscore, and the first 5 letters of the client name. For example: Local HD/images/100308_matpe.
If your images are in need of organizing, you can do one of three things: invest in cataloging software (expect to pay $200-300 a reasonable package like Aperture (Mac) or Lightroom (Mac, Windows)); systematically find the folders containing your images and recreate the folder (with images) in a new and structured file system; or use Mac OSX “spotlight” to locate all of the image files at once and either copy or move them to a new folder.
While the last choice is fastest and easiest, it will result in a giant collection of image files in a single folder. If the original folders provided a means of identification, you’ll need to sort through all of the files and either rename them or recreate sub folders for identification (very time consuming).
Quality cataloging programs will allow you to either leave the image files as they are and access them via the catalog (the program will find your image files for you), or you can use the program to move or copy the files, with their identifying folders, to a new location (your structured file system).
Of course, you can take the time to systematically cull the images by looking in all of the folders on your computer and then manually copying or moving them to a new location (your structured file system). The benefit of this approach is that you will discover important lost or misplaced non-image files as well. And you can clean up your hard drive by reorganizing, backing up, and deleting files as needed.
If you are choosing the last, “spotlight” method, be very mindful that you do not lose whatever identification / folder system you do have. Access “Spotlight” my clicking on the magnifying lass icon in the topmost, upper right of your desktop. Type “.” In the search field and hit enter.
Click on “kind” in the right-hand window titled “sort within group by”, the click on the blue “more images” option at the bottom of the images list (you may have to scroll down to find the images list).
These steps will produce a list of ALL of the image files on your Mac. You can select a range of files to move or copy by clicking on the first file in a series, then shift-click (hold down the shift key while clicking) on the last file in the series. You can add or remove selections by control-clicking on individual files.
DANGER: do not alter files unless you are confident of the changes you are making – if you are moving files, you are making permanent changes to your computer system and you can easily misplace image files that belong to the operating system or to other programs. Copying files is safer than moving them. Unless you are backing up, be careful to avoid creating duplicate sets of images. If you are backing up, you DO want to duplicate your files (on a separate hard drive (or other media) for safe keeping. It would not be a bad idea to back up your system with Time Machine or another backup program before moving files.
Hope this is helpful. And again, please add anything I might have missed. Thanks.
Posted in Digital Preservation, How To, Photography.
– March 11, 2010
Canon EOS 1D Mark IV vs Nikon D3s – BOGUS?!
http://www.dxomark.com/index.php/eng/DxOMark-Sensor/DxOMark-reviews/Canon-EOS-1D-Mark-IV-vs-Nikon-D3s
Canon 1D Mark IV (16.1 MP, 4896×3264)
Nikon D3s (12.1 MP, 4256×2832)
It seems like common sense. The Canon Mark IV images are 1.15 times bigger than the D3s images. If they are not downsampled before comparing and contrasting, pretty much all aspects of the Canon’s performance will seem poorer than the Nikon’s. For example: the same high performance lens (Zeiss, Digitar, etc.) mounted on both cameras will ‘yield’ different levels of resolving power or sharpness. Downsampling the Canon images will pretty much fix this. I wonder if anyone has tried this for comparing other performance aspects.
I determined size ratio by measuring the diagonals of the two sensors; the Canon is 1.15 times bigger.
Posted in Uncategorized.
– February 23, 2010
Low, low, low light: getting it in focus
I’m just back from shooting a week-long NSM in Scottsdale. Typically, I’m asked to shoot all of the events, not just the ones with stage lighting. This means making great pictures happen in dim and cavernous conference and ballrooms full of people.
For such occasions, I keep a few wide angle lenses in the bag. A trick I learned from a really old-time press photographer (we’re talking Speed Graflex days, here) is to shoot it wide and crop it down. Back in the day, photogs would often stop down to f8 and focus at 4 meters or so to better the odds of getting decent pictures. The compositions were pretty much ‘one size fits all’ and they would crop their view camera film to frame their subjects.
Oddly enough, even the most advanced DSLRs and lenses have a hard time focusing in extremely low, even light, bringing it all full-circle. Getting closer to the subject helps the camera focus. I’m sure to make a few of these pictures. However, getting close also means wider angle, barreled images. You can’t shoot an entire venue with a fisheye.
What you can do, is use your fisheye or super-wide from a few meters away and crop out the distorted parts. Much more manageable. At f2.8 or 4, the depth of field is much greater than you’d get with a 50mm or an 85mm. You can’t avoid getting some soft focus pictures in these situations, but you can tip the scale a bit and give yourself a chance of making more workable photos.
Oh, and you’ll probably end up switching off or fighting the auto focus, so using your old manual backup 35mm is seriously an option (and a third the weight).
Posted in How To, Photography.
– January 30, 2010
ISO 4000: How to get that amazing sports shot
When I shoot sports, I use photos where you can clearly see the puck, ball, frisbee, what-have-you. Personally, I think it’s important for those shots to be as sharp as possible. I’m not a big fan of washy-looking pucks and mushy basketballs; I like seeing the nicks, and dimples. At the very least, the ball should look like a ball.
Because of my attitude, I use a pretty high ISO. My most used sports lenses are the 80-200mm and the 400mm. The majority of hockey and basketball images are made at f2.8 with 1/1000 sec. shutter speed. ISO ranges from 3200 to 4000.
Many of my colleagues have challenged my philosophy and technique. I don’t argue; I figure that there’s something to be gained from hearing them out and learning their approach. In some cases, like collecting headshots for the media guide, or getting that breathtaking shot for a marketing poster, I agree that using a much lower setting is important for minimizing or eliminating the graininess. Getting a sharp image aint easy, though.
Generally, however, sports photography is destined for print or web articles and slideshows, where ISO 4000 pictures hold up very well. Even as 8 by 10s, they look pretty awesome.
Below is a picture I took of Northeastern Husky, hitting a whistler of a slapshot. Admittedly, not one of my best pictures, it does make my point. The image size is pretty close to what you’d see in a paper, magazine or on the web. Clicking on the image will get you a larger version, typical of what you’d see online or in print.
- Northeastern Huskies Kyle Kraemer
Yes it looks great smaller, and yes the full res version a bit grainy. The player, puck, and the stick (and usually the sweat, spit and ice shavings) are very sharp. And beautiful. The image does look a bit soft because of the scraped-up plexi I shot through to get it. Sadly unavoidable; unlike the Garden, Mathews Arena doesn’t have photographer cutouts, which is typical of AHL and college rinks.
Here I’ve added a couple of details of the puck and face. Again, not going to make a good yearbook headshot, but then again, not really the point of this photo. These crops are from the 240ppi 8 by 10 version.
- full resolution detail of the puck
full resolution detail of the face
It wasn’t until I picked up the D700 and the D3, that these images (for me) were really possible. My D2X pictures fell apart at after 1600 and The D2H – well, forget it. The newer camera processors are used to accomplish close to medium format quality with the most advanced DSLR features. I’d considered trying to shoot with a Mamiya (and then probably shooting myself) to get high ISO with low noise or grain. The thought of trying to use the studio camera for high action sports makes my tummy hurt.
So, that is why I often use 4000 and that’s why I have such an appreciation for those sharp pictures. Again, not for every occasion and not for every shooter. Whether or not it’s workable, I think you can pretty well judge for yourself; look closely at your favorite sports photos. If you find that the ones you like best are tack-sharp, maybe it’s time to give high ISO a try.
Posted in How To, Photography.
– January 11, 2010
10 steps to photographic quality from your DSLR!
Having taught Intro to Photography for many years, I’ve seen more than my quota of gravestone pictures. However, I couldn’t resist taking a few pictures in the Mount Auburn Cemetery on such a nice day. The image I chose for this tutorial was created with a Nikon D700 with an AIS, manual 55mm lens. The original file was a JPEG, saved with the Adobe RGB (1998) colorspace. The following tutorial demonstrates a practical and easy way to transcend the DSLR ‘look’ and make your pictures resemble film photography.
I’ve provided screenshots for the PC version of Adobe Photoshop Elements, the software mostly used by my students. The technique outlined in this tutorial can be used with Adobe Photoshop CS4 (and earlier versions), for greater control and nuance. The basics, however, are the same for both applications.
Step 1. After opening your image, duplicate the main/Background layer by choosing Layer/Duplicate Layer (ctrl-J)
Step 2. With the new layer selected, apply “unsharp mask” (Effects panel/sharpen/unsharp mask for Elements or Filter/sharpen/unsharpmask for Photoshop). I usually use settings close to threshold: 0, Radius: 1.4, Amount: 65 Because this technique offers a good deal of latitude, I tend to use higher settings, which I then experiment with. It’s worth noting that the settings tend to be consistent for camera body and lens combinations; later on, you can save time by creating Photoshop actions or by remembering your Elements settings.
Step 3. Duplicate the sharpened layer. It might be helpful to give the two sharpened layers new names. I’ve called mine “sharpened_dark” and “sharpened_light”. Admittedly, I only rename the layers when I think I’ll need to perform extra work on the file later on.
Step 4. Change the blending modes of the respecitve layers to darken and lighten and adjust the opacity until the image looks improved, but not artificially sharpened. To accomplish this, try toggling the layer visibility (little eye symbol) on and off. I find that the darken layer usually has a higher opacity.
Step 5. This next step will be helpful if you want to darken or lighten all or part of your pictures (I’ll discuss “dodging and burning”, locally darkening and lightening later on). Click on the half moon cookie symbol at the bottom of the Layers palette and add a Levels adjustment layer (or Curves if you’re using Photoshop). Make some quick adjustments, which you can refine later with the layer’s opacity setting.
Step 6. Add a Hue/Saturation adjustment layer, also accessibly via the half moon cookie symbol. With the colorize box checked, set the Saturation to something close to 13 and the Hue, initially, to somewhere around 36. I find that of all of the settings so far, Hue varies most of all depending on camera, lens, time of day, exposure, etc.
Step 7. Return to the layers palette and set the Hue/Saturation layer blending mode to “Overlay”.
Step 8. The layer opacity will also need to change; I find that settings between 15 and 30 work well, but you shouldn’t rule out higher or lower settings. I closely watch the darkest values of the image in order to avoid blocking up/clipping the values by using too high of a setting.
Step 9. Refine any or all of your adjustments by clicking on the layers and changing the settings or by increasing or decreasing the layer opacity. On very, very rare occasions, I duplicate the Hue/Saturation layer so I can fine tune with two different Hue settings.
Step 10. Finally, save your file. I often save the work file, with all of the layers, as a PSD. Ultimately, you’ll want to flatten the image (Layer/flatten image) and save as a JPEG or TIFF. JPEGs are much more common because of their size. I use a quality factor setting of 10 or higher for most of my JPEGs, unless I’m creating thumbnails or small reference images for attaching to emails.
While the original image (left) has a red bias and muddy look, the adjusted file has a photographic film-like appearance
Working in Photoshop allows me to save this process as an action. Depending on the camera make and model, these steps are automatically applied to newly opened images. If I like what I see, I save the result. If not, I use the History palette (Undo history in Elements) to unflatten the layers for further refining. The results look great, but they are far from perfect. For technical and studio photography, my workflow is very different. However, for most photojournalism and for my personal pictures, this approach really does the trick without having to delve into color profiling and intense tonal mapping.
Much of this approach is based on the guidance and support of my newsroom colleagues and from tips and tricks found throughtout my extensive library. A couple of books from which you might find helpful for getting a start are:
Real World Digital Photography
The Adobe Photoshop CS4 Book for Digital Photographers
I believe that The Mount Auburn Cemetery is the most beautiful in the country. It is a destination for music, art, flora, bird watching, history and more. If you’re in town, it’s worth checking out. (checking in is another story).
Posted in How To, Photography.
– December 4, 2009
3 Keys to Successfully Backing Up Your Image Files (and other electronic records)
Last year, when I began updating and refreshing my backed up image library, I discovered that many of the DVDs I had used for storing my photos were no longer readable. Making matters worse, about twenty of the backups were also corrupt. I used expensive software to recover about 70-80% of the corrupt media, but the process for finding and extracting usable files from bad DVDs and comparing them to their corrupted backups took weeks. In 2000, backing up to CD and DVD seemed like a smart thing to do. If I only knew then what I know now…
Securing and properly managing digital objects will ensure that they will last for years and generations to come. While there are many guidelines and best practices that describe digital preservation, the steps and tools are not always clear. The paragraphs below offer my personal, practical approach for backing up and maintaining an image library.
Put simply, three keys to solid digital asset preservation are: Backup regularly, store multiple copies in different locations, and establish a 
program for refreshing and verifying the data.
Backing up on a regular basis
I generally don’t trust off-the-shelf external drives. Instead, I keep current with technological developments and product evaluation in order to choose the most reliable media. At the moment, I’m using Seagate Barracuda 7200.11 and 7200.12 500GB hard drives, which I buy as OEM for around $50, each. I chose quality aluminum enclosures for the drives at around $40 apiece (http://www.rosewill.com/products/917/productDetail.htm). The units take about 10 minutes to assemble and are plug-and-play.
I’ve had success with lesser expensive enclosures; the drive that sits inside needs to be reliable.
On a Windows machine, I use Karen’s Replicator (http://www.karenware.com/powertools/ptreplicator.asp) for weekly and daily mirroring/backing up of the image library. This tool offers incrementally backing up files, which means that only newly added data is copied onto the external drives.
When I’m working with Macs, I sometimes use Super Duper (http://www.shirt-pocket.com/SuperDuper/SuperDuperDescription.html).
There are other great backup utilities for Mac, Windows, and Linux; I’m hoping that readers will share their suggestions and experiences with us in the Forum section of my website.
I keep three mirrored sets of my image library. One set remains on my workstation computer. A second set is kept on an external drive, which I keep in a closet in another part of the house. The third exists on a drive that lives in a fire-proof box on a shelf in my studio.
Many best practices and disaster plans advocate storing backups in a different region of the country to better safeguard against major catastrophes. If it’s practical, I strongly recommend it (Twice a year, I send sets of my files to my sister, who lives 1400 miles away).
Alternatively, a backup could be stored remotely with an online service such as Idrive, Barracuda Networks, Carbonite, MozyHome Online Backup, SOS Online Backup, Iron Mountain, etc. If you choose this option it’s important to do your research and to pick a provider who’ll be in business years, if not months from now.
I’ve also heard of cases where USB Flash drives and external hard drives are stored in Bank safe deposit boxes, which also sounds like a good idea.
Refreshing
The life expectancy of an actively used hard drive is generally about 5 years. A drive used soley for backups will likely last longer. Common sense tells us that although the drive may last for decades, it is imperative that we refresh or move the data to newer media on a regular basis. Just think of your uncle’s prized laser disk collection, which he can no longer enjoy because the format is obsolete. There is no guarantee that today’s technology will be supported a decade from now. I expect to update my storage media at least once every five years.
Verifying
We also need to maintain our collection and its backup. Regardless of the media and transfer methods, occasional data loss should be expected. Creating checksums (a short code that summarizes or describes data) is a great way for monitoring a backup’s digital health. Before creating my backup, I generate checksums for all of my files. I verify the checksums anytime I transfer the data from one piece of media to another. My regular maintenance includes verifying checksums on all of the media, which I do every other month.
On my Windows worksation, I use EF Checksum Manager (http://www.efsoftware.com/cm/e.htm)
and on my Mac, I use MD5 Checksum Verifier (http://md5-checksum-verifier.software.informer.com/screenshot/15831/)
Alternative checksum software suggestions have included MD5 Summer, MD5 2.6, Checksum Validator. There are many others; I encourage readers to share their experiences in the Forum section of matpearson.com.
While it might seem overwhelming at first, developing an approach for good digital asset preservation is relatively easy. My personal policies work well for me and will probably work well for others, but we really need to develop programs suited for our level of understanding and the resources we can commit. To best accomplish this, we also need to keep current with best practices in the field. And above all, we need to remain disciplined and organized.
* While there are many resources for keeping current with best practices, I’m including a few that I
and my colleagues have found helpful over the years…
Bibliographical Center for Research (formerly Colorado Digitization Program) Best Practices
http://www.bcr.org/cdp/best/digital-imaging-bp.pdf
Moving Theory into Practice: Digital Imaging Tutorail from Cornell University
http://www.library.cornell.edu/preservation/tutorial/preservation/preservation-03.html
NINCH Guide to Good Practice in the Digital Representation and Management of Cultural Heritage Materials
http://www.nyu.edu/its/humanities/ninchguide/XIV/
Posted in Digital Preservation, How To.
– November 19, 2009
300ppi? How to Determine your Digitization Project Needs
Introduction
Digital preservation projects typically require that materials be imaged at a “Best Practice” standard of either 300 or 600 pixels per inch (ppi) for actual-size representation, often without a clear understanding of why or how these rigid guidelines are important. Digitizing large quantities or oversize materials can be overly demanding of staff and resources in many cases. There are opportunities for using a lower, more manageable ppi and there are situations when a very high number of ppi is necessary. To ensure overall project success, it is important that the choice of ppi be a rational and informed one.
The following article includes some helpful advice for understanding how to calculate sample frequency / ppi based on need. At a glance, the formulas may seem complicated, but rest assured, the math is actually quite simple. The sections that follow begin with a brief review of terminology, followed by an overview of an approach for determining ppi needs, a case study in which 300 ppi is preferred, and some additional considerations.
Terminology
Pixels (picture elements) are the fundamental units of digital image files. They are arranged in a grid and vary in brightness and/or color.
Pixel size varies and is a characteristic of imaging devices as well as electronic image files. A 33 megapixel digital camera back might have pixel sizes of 7.2 x 7.2 microns while a graphics LCD might have a pixel size of 127 x 127 microns. Image file pixel sizes are determined by sample frequency, which is established within imaging device driver software or image editing programs. The relationship of device pixels to image file pixels is somewhat similar to that of film grain to photographic enlargements and projected film.
Sample frequency is usually expressed as pixels per inch (ppi), the number of pixels within one inch of the width or the height of an image file. The term “resolution”, the ability to distinguish detail, is commonly misused to refer to sample frequency. For readability and clarity, this paper employs “sample frequency”.
Pixel Dimensions refers to the number of pixels in the length and width of an image file.
Megapixels generally refers to the total number of pixels an imaging device can record: the product of multiplying the number of pixels in the length of a device’s potential image file by the number of pixels in its width. Megapixels is commonly used in marketing for digital cameras and rarely used for describing image files.
A very basic approach
Examine the details closely. Determine the smallest element to be recorded and measure its smallest dimension. If it’s a mark from a technical pencil, its width might be between .0118 and .063 inches (standard technical pencil lead sizes).
Divide 1 by the smallest element’s smallest dimension (in inches) to determine the number of details that would fit side-by-side into an inch. Round the quotient up in order to convert to pixels per inch. The number of technical pencil marks that would measure up to 1 inch is between 84.74 and 15.87; the absolute sample frequency for recording any of them is between 85 and 16 ppi.
1 / .0118 inch = 84.74 details / inch = 85 ppi
1 / .063 inch = 15.87 details / inch = 16 ppi
PPI, practical sample frequencies, and extended usefulness
In the illustration to the left, the letter “e” measures ten pixels wide. If twenty pixels span one inch of the image file’s entire width or height, its sample frequency is expressed as 20 ppi and the letter “e” is determined to be ½ inch wide.
“Lines per inch” is an extension of pixels per inch where a line represents a row or column that is one pixel wide. The 20 ppi file’s image could portray 20 horizontal or vertical lines per inch.
Without variation in tonality or color, 20 side-by-side lines would display as an amorphous mass. For this reason, we use alternating black and white lines (line pairs), which are traditionally used in evaluating the resolving power of optical systems. To better represent detail with pairs of lines or pixels, 40 ppi is used for recording the letter “e” and for our small pencil mark, a minimum sample frequency of 170 ppi.
The problem of “scattered pixels” provides an argument for using twice the minimum sample frequency for representing discernible diagonal line pairs. Pixel-wide vertical and horizontal lines are more easily represented than pixel-wide diagonals. Regardless of capture / scanning device capabilities and limitations, minute details are vulnerable to a degree of aliasing or pixel scattering during capture and processing phases.
The top left illustration shows a potential effect of rotating an image file. Although the lines can (arguably) be discerned, there are not enough pixels for well-defined edges.
The top right illustration’s line pairs were captured with a practical sample frequency of twice as many pixels per inch. Some tools (Adobe Photoshop, ImageMagick, etc.) are very good at resampling for basic image manipulations such as rotation. However, there is no way to guarantee which applications will be used in future work with the image file. Providing the smallest important details with two or more pixels instead of one is a good rule of thumb for ensuring readability. When doubling, multiply the minimum sample frequency by 2.
A review
Absolute sample frequency: one pixel or line represents one image detail
Minimum sample frequency: two pixels or lines represent one image detail
Practical Sample frequency: four pixels or lines represent one image detail
Theory into practice: A case for 300 ppi
An image file with readable markings was the primary goal for digitizing the blueprint illustrated to the right. Markings indicated by the red circles suggest the scale of typical important details. The lines smallest dimensions measured .014 inches, requiring an absolute sample frequency of close to 75 ppi. At a minimum sample frequency of 150 ppi, line edges were better defined, improving legibility and the overall appearance of the image. The sample frequency was further doubled to a practical 300 ppi, safeguarding against aliasing and extending the usefulness of the image file.
Doubling the minimum sample frequency introduced a second level of information, which included minor paper damage and a suggestion of paper texture. The final representation of the .014 inch line was 3 to 4 pixels wide. At 150 ppi, the same line would have been recorded with a width of only 1 or 2 pixels. The 300 ppi image file can be resized or downsampled as needed; greater detail, however, can only be achieved by re-digitizing the blueprint, subjecting it to more handling and harmful light exposure.
Tables
The following tables provide sample frequencies for detail sizes in inches and millimeters.
| Minmum sample frequency / ppi | Practical sample frequency / ppi | Dimension of smallest recorded detail |
| 36 ppi | 72 ppi | 1/18 inch |
| 72 ppi | 136ppi | 1/36 inch |
| 100 ppi | 200 ppi | 1/50 inch |
| 150 ppi | 300 ppi | 1/75 inch |
| 200 ppi | 400 ppi | 1/100 inch |
| 300 ppi | 600 ppi | 1/150 inch |
| 400 ppi | 800 ppi | 1/200 inch |
| 600 ppi | 1200 ppi | 1/300 inch |
| 800 ppi | 1600 ppi | 1/400 inch |
| Minmum sample frequency / ppi | Practical sample frequency / ppi | Dimension of smallest recorded detail |
| 36 ppi | 72 ppi | 1.42mm (1.411mm) |
| 72 ppi | 136 ppi | .71 mm (.705 mm) |
| 100 ppi | 200 ppi | .51 mm (.508 mm) |
| 150 ppi | 300 ppi | .34 mm (.339 mm) |
| 200 ppi | 400 ppi | .26 mm (.254 mm) |
| 300 ppi | 600 ppi | .17 mm (.169mm) |
| 400 ppi | 800 ppi | .13 mm (.127 mm) |
| 600 ppi | 1200 ppi | .09 mm (.085 mm) |
| 800 ppi | 1600 ppi | .07 mm (.064 mm) |
Putting the details into greater perspective: when too much is not enough
Consider scans / captures made at 300 ppi. The smallest recorded detail could measure .007 inches (about half the width of a fine technical pencil mark). Sometimes it is important to record information of that scale: for example, in the case of object damage (staining, cracking, etc.) where the damage will be visually analyzed. However, a 300 ppi scan / capture does not come close to recording detail on the scale of paper fiber.
Typical paper fiber widths range from 15 micrometers to 30 micrometers. A conservator wishing to record details of this scale, for a digitized A4-size object, would ask for a file size of 14,069 pixels by 19,832 pixels, based on the following:
- detail measurements of 15 micrometers to 30 micrometers
- minimum sample frequency of 1,695 ppi to 3390 ppi
- image file dimensions of 14,069 pixels by 19,832 pixels; a 16-bit file size of greater than 1.5 gigabytes
For recording paper fiber-scale detail, a very strong case can be made for capturing a portion of the object at very high magnification or for waiting a few years for imaging technology to catch up with demand.
Additional considerations
Performance and resolution
Lens or optical issues and device performance factor into the resolution of digitizing systems. Since the aim of this article is to provide a basic understanding of how and why sample frequency is considered in digital reformatting, lengthy discussions of the impact of lens resolution and approaches for compensating have regretfully been sidestepped. It is important to note that the ability to record detail is also dependent on the quality of the optical systems employed.
Recording texture
Lighting is an important contributor in recording detail for textured and three dimensional objects. Using a very high sample frequency will not always provide satisfactory detail. Nuanced lighting is often necessary for revealing textures and details that might be lost with the uniform illumination of flatbed scanners. The complexities of successful lighting for photography are within the domain of a skilled and experienced photographer.
Preserving edges
Image borders are often an unavoidable necessity for archival imaging. Since perfectly square objects are a rarity, uniform image borders are often tolerated for the sake of preserving object shape and edge detail. When incorporating borders, sample frequency may need to be adjusted for digitization projects where pixel dimensions are a determining project guideline.
Conclusion
When selecting materials and establishing guidelines for a digitization projects, the details must not be overlooked. It is important to examine the materials, to identify the smallest information that needs to be recorded, and to determine sample frequency case by case. For many projects, 300 ppi or 600 ppi makes perfect sense. There are situations in which lower resolution is appropriate. If the project merits it, there are techniques for achieving much higher resolution as well. For any digitization project, a basic understanding and appreciation of sample frequency is essential for making the most practical, informed decisions when establishing guidelines.
Posted in Digital Preservation, How To, Photography.
– November 13, 2009
Nearing the finish line!
Update: the new website should be live sometime on Monday, November 16th. I’m sorry for any inconvenience the reconstruction has caused and I’m thankful for your patience. PLEASE let me know of any any bugs and definitely check out the mobile site with your handhelds (http://matpearson.com/mobile until I have the redirect script in place).
For those who have been following, you’re noticing some big changes. As I transition to a new website and networking, this blog, the forums, the galleries and matpearson.com will have a whole new look and content to match!
The forums will offer e-learning tools and a place to practice them. It is and always will be a work in progress and I hope you’ll join me in making this an efficient and up-to-date resource.
The blog will include tips, tricks, news, and reviews, which you’ll find useful and enjoy following.
The site will have a whole new look in two phases, the first in mid-November and the second in March. I’ll be updating the galleries with new material and building-out a better client section.
I’ll do my best to keep posting over the next few weeks as I tackle these projects.
Best,
Matt
Posted in Uncategorized.
– October 28, 2009
13 Steps for Photographing Professional Sports: Never let them see you sweat!
Goalie Ron Tugnutt struggles as the Boston Bruins defeat the Dallas Stars, 1-4 at the Fleet Center. (photo/Matt Pearson)
Photographing games can be hectic. For professional sports, pile on the stress of dealing with very tight deadlines, aggressive security personnel, and drunk fans out to spoil your day. Since shooting these events freelance and offering images on spec doesn’t pay much, being organized is important for preserving energy and maintaining morale and a cheery disposition. I find that I get more work and sell more photos when I leave a good impression. Oh, and never let them see you sweat!
Workflow
- Print out team rosters, event info and directions
- Photograph game/event
- Note photo IDs for individuals and image numbers
- Be sure to ask for name, age, and hometown when photographing spectators
- After the event, at home or on location, ingest image files to dated folder
- Backup ingested folder
- Edit down to selects using PhotoMechanic
- Add IPTC metadata using PhotoMechanic
- Add personal notes, ratings, flags, etc.
- Edit Selects in Photoshop
- Apply global actions, such as sharpening, noise reduction, color and tonal adjustments
- Resize to 10”, 300ppi and save as JPEGs with AdobeRGB colorspace and quality factor 10
- Resize again to 800px, 72ppi and save as JPEGs with sRGB colorspace and quality factor 5
- FTP 10” edited selects to client FTP folder
- Find client contact info in address book
- Email 800px versions to client, following up with a phone call
- Update the backup folder
Time
The total time needed for a college sports shoot might add up to three or four hours. Allow five minutes for printing out information and loading up the vehicle. Another half hour to forty-five minutes for travel arrive fifteen minutes before the event starts and shoot for an hour. Take another half hour to forty-five minutes to pack up and head home. Ingest and editing usually takes half an hour. Emailing, FTP-ing and backing up files might add another fifteen minutes. Note that the camera work adds up to a mere fraction of the total time spent on an assignment. And this is with a very organized address book, calendar and workflow.
Posted in How To, News, Photography.
– October 24, 2009
