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Any copying or reproduction is strictly prohibited under Federal Laws.

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Anyone can take pictures ~
We Create Lasting Portraits!

Full Service Portrait Studio
Est. 1977

Full Service Photography ~
with the
Personal Touch you deserve!
Full Service Portrait Studio
Est. 1952
P. O. Box 930302 ~ Verona, WI 53593 - USA   /   (608) 873-6934 or 516-0870

This page links you to the technical
and incidental aspects of various topics
From photography, to computers, to flying, and more

Image Comparison of
Copy or Web Quality
vs Studio Quality

Hand Oiling A Black & White Museum Quality Image

Why NOT to Use Scans & CDs!
If you are Archiving your treasured images
See example

How to extend the life of your photos

Color Balance Info (sending digital files) Scan Resolution Ref. (proper scan res to match final output) File Resolution Reference (guide to relative file sizes)  PPI ~ DPI ~ LPI
Understanding the differences
Miscellaneous Questions & Answers
Questions
First: Defining a few file formats (these are very general descriptions and not intended as definitive)

... My images are 2.5mb jpegs scanned onto cd Now they're up to 14 megs? How did you get from A to B?

... This really bugs me .... You pay for stock images according to how big the file size is but what you get is a MUCH smaller file ... If I buy a 10 meg file, I want it to be a 10 meg file when I get it.

... After I downloaded an image from my digital camera Photoshop shows an RGB file with a size of 4.4M and 13.92 X 21.33 inches dimensions or approx 1500x1000 pixels. That's big!

... I think should web images be prepared at 72 ppi. Web images are slow to load when largest dimension is greater than around 500 ppi. Photoshop will tell you the inch dimension.

... Exactly how does "depth-of-field" work? I heard Telephoto lens have less "depth-of-field.

Responses © EIS
Some File Formats:

.BMP - A format native and almost exclusive to PC/Windows
.PICT - A format native and almost exclusive to Mac

Neither of the above are recommended for any serious image manipulation or file sharing.

PSD - The native file used in Photoshop which allows retention of all Photoshop manipulations

.TIF - A complete (raster) image file with all information retained (also called a "lossless" file, even when compressed with LZW. This is the "ideal" file format for retaining image quality. However, it is typically very large file size for a given image.

With the introduction of Photoshop 7, TIFFs can now be saved with layers (and can be compressed). These options has become the scourge of most every print house and image user as most programs can NOT recognize or use these types of files. Unless specifically asked, do NOT save TIFFs with layers or any compression (TIFFs with layers can also become enormous file sizes.)

.EPS - A vector based file using mathematical relationship to describe the image. Vector images can be varied in size, from a postage stamp to a billboard, without any loss of quality (i.e. jaggies). Most often used to design logos, illustrations and other graphics (with programs like Illustrator or Freehand). Some printing houses also prefer receiving final Photoshop files as eps, because once the raster image is converted to vector, it is much more difficult to induce changes and (unwanted) alterations.

.GIF - A format limited to between 2 and 256 colors and used primarily for logos and minimum color variant work for the web. Advantages are that it allows transparent backgrounds, animation and often smaller file size (though not always) than a comparable JPG. Generally not recommended for web photos (and definitely not for printed images).

.PDF - An Adobe Acrobat file. These files are primarily intended as a "universal" document format which can allow almost any type of computer system (with the associated software "reader") to view or read the document (whether it be text or images) and regardless of original application source. These files are not intended to allow manipulation by the recipient. As with .eps, some printing houses prefer receiving final Photoshop files as .pdf.

.JPG - A raster image which essentially represents a TIFF, with various amounts of information deleted from the image in order to reduce the file size. This is called a "lossy" format. A nominal compression or size reduction retains the highest image quality. The higher the compression (more file size reduction), the lower the image quality. Deleted information, resulting from a JPG format can NEVER be recovered! Lost information can be synthesized, but never reconstituted.

In an attempt to offer a very simplistic explanation: If you had a beautiful TIFF image with 10,000 variants of color, out of millions of possible colors, a TIFF save would not only save the 10,000 existing colors, it would also save the potential space for the rest of the colors as well. If you save that TIFF image as a maximum quality JPEG image, it would save the 10,000 existing colors but not the reserve space for the remaining potential values. Hence the file size would be reduced or "compressed".

On the extreme, if you saved the same image at the highest compression (lowest quality), the compression scheme would actually average the colors, and other image information down to the bare minimum representation. For example a hundred shades or variants of green might be averaged to just one green, - the same with all the other information, so the the final compressed image may only have a a few hundred colors, of what used to be thousands. (You can actually see this by enlarging a highly compressed JPEG and comparing it to the original). Again remember, deleted information can NEVER be recovered!

When you open a JPEG, you actually are expanding it back to its original TIFF file size. The extent of the JPEG compression will determine how much original information will still be retained in the display (and how much quality you will recover after opening).

Do NOT work in a JPEG format! Every time the same image is saved as a JPEG, the image quality progressively gets worse. If you have a JPEG, save it as a TIFF or PSD before you do any work or manipulation with it. Only save it again as a JPEG when all the work is completed and NO more manipulation will be done on the image - by anyone!

JPEGs are best for minimizing the storage and transfer file size (i.e. emails, web pages, etc.)

In association with a local printing house, we have done various test printing on a high end color press, using both TIFFs and high quality JPEGS. As long as no (or minimal) manipulation was done to the JPEGs, there was NO discernible difference between a press run four color 150 lpi TIFF and a JPEG, even under a loupe. However, the big difference was having a 2 MB JPEG file versus a 14 MB TIFF file. The former could be emailed while the later had to be shipped on a CD or hand delivered.

(There is now a JPEG 2000 being released. Best bet is to let it mature a bit.) (Back to Questions)

Expanding File Size: The 14 MBs represents the same image uncompressed versus the compressed 2.5 MB JPEG. (Back to Questions)
Cost for Digital Files: You probably are being charged for the 10 MB file, because when you open it and use it, it will be 10 MBs. The real question which needs to be asked is to what degree (Quality) have they compressed the original image?

JPEGs certainly do make sense when transferring files. When used effectively, it can also restrict unwanted manipulation of the received file. So has long as you don't extensively modify what you bought, it should work just fine and you got what you paid for. (Back to Questions)
Large Camera Image: BUT - those dimensions are for 72 ppi. If you want to print that image, without interpolation (synthesizing) and used a standard default of 300 PPI, your actual image size is only 3.3" x 5.1". (Back to Questions)
Should web Images prepared at 72 ppi by X inches? Not exactly. Web image can only be related to the height and width in PIXELS. For web work, there is no such thing as image resolution, in the sense of pixels per inch.

The 72 ppi came into being as a result of centuries of traditional publishing and page layout practices where the standard measurement is 72 points per inch (actually 72.27). When the Macintosh was designed, its entire operating system and premise was to serve the print and graphics industry. Hence, one of the attributes of their design was to have 72 pixels of display per inch (equal to 72 points per inch) and resulting in a near perfect computer display for press production. (PC/Windows on the other hand defaults to 96 pixels per inch, plus a different color gamma as well.)

The 72 ppi was carried over as a defacto into web work as well (as the web occurred long after page design was established). This worked reasonably well for earlier 12" or 13" CRT monitor displays. But as larger monitors became available and as newer video hardware designs allowed for higher screen resolutions (i.e. from 640 x 480 pixel display to 1920 x 1200 or more), these web "standards" have somewhat disappeared (along with "web safe" colors).

For example: if you created an image that was dimensionally 640 x 480 pixels and had a screen display that was 72 ppi, the width of the display image would be 8.9 physical inches (640 / 72) on the screen. That same 640 x 480 image display, using 96 ppi screen resolution would only be 6.7 physical inches (640 / 96) on the screen.

Another way of thinking about it is lets say you created a 6" long image which you displayed at 72 ppi. This would result in a total length of 432 pixels (72 ppi x 6"). If we took this same 432 pixel image and changed the monitor screen resolution from 640 pixel width to 1,920 pixel width, that same very 432 image would now be displayed in 2" physical inches (640 / 1,920 = .333 and .333 x 6" = 2"). It is exactly the same size image (432 pixels), but its display size went from 6" down to 2" because of way the screen monitor resolution was set.

So in reality, when it comes to web work (not knowing how big the viewer's monitor is or what they have set their display resolution set to) there is no correlation what-so-ever to physical inches. Web images are ONLY measured in HxW pixels. (Also see the previous response to "Large Camera Image"). (Back to Questions)
Depth-of-field: Depth-of-field is a function of image magnification, regardless of lens focal length. (By the way, a telephoto lenses is definitely preferred for portraits, at least twice the focal length of a "normal" lens - any format camera.)

For example: if you shoot a group of people, full length, and for the sake of discussion, the individual head size is about 1/4" on the (35mm) film plane, You could set your lens aperture at F:1.4 and still get a reasonably sharp background (even with a background a 1/2 mile away). On the other hand, on a head shot, if the head alone fills the entire film frame, even F:16 may not be enough keep everything from the nose to the back of the head acceptably sharp.

For reference, "acceptably sharp" is somewhat subjective. Although it is based on the maximum allowable size of the circles-of-confusion, and there are published guidelines, there are no absolute dictates as to a specific maximum. In fact, not only can it vary from interpretation to interpretation, it also varies (rather consistently) from one format to another. And with respect to circles-of-confusion (all other things being equal), a 35mm lens can cut twice as sharp an image as a 4x5 lens!

There a general rule about the RATIO of acceptable sharpness, which is: Depth-of-Field provides for one unit of distance in front and two units of distance behind the point of focus to be acceptably sharp. The actual physical distance is dependant on both the image magnification and the F:stop used.

By the way (this one drives me nuts!), You may hear the term "Depth-of-Focus" tossed about. There is NO such thing as "Depth-of-Focus"! It DOESN'T EXIST! There is only ONE POINT of FOCUS (no lens can focus on two different distances at the same time!) Everything else is "Depth-of-FIELD"! And any yahoo who uses the term "Depth-of-Focus" is blowin' it out their ear and I'd take anything they say as a grain of salt (a very small grain)! - End of rant.

You might also want to pick up Kodak's "Professional Photoguide" book (R-28, cat 104 2282) which offers a tremendous amount of information, including some depth-of-field scales. (It may not have your lens/format combination in their circular rule, but if you play with the dial a bit, you should get a much better grasp on the principles.) (Back to Questions)

This commercially produced CD is only two years old.

It was sold by a major software company with their application and installation program.

The CD was stored in a workroom bookshelf, protected from light, excess humidity and kept at standard room temperature (approx. 70° F).

These cracks appeared less than two years after manufacture (based on Copyright declaration on CD front).

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