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Information sheets on design, illustration, digital imaging, photography and other related topics. Compiled and written for my clients, students, and my own work. Provided here for your convenience. If you take information form these sheets to use elsewhere, please provide the appropriate credits along with the information.

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Kodak Photo CD

Using PhotoCD Images

The Kodak Guide to Imaging ($12.95) covers digital camera, color proofing, image output, and PhotoCD. Kodak has several published handbooks that cover PhotoCD. As technology evolves the publications change. Kodak Professional: Resources , the latest Acquire Module for Photoshop, which is now "(once again) better than just using Open in Photoshop".KODAK Photo CD Acquire Module Download Page, KODAK: Photo CD Technical Papers, and Using KODAK DIGITAL SCIENCE PHOTO CD Discs for Graphic Arts. [Quotations are from Howard Brainen, owner of Custom Process, and a specialist in the production of Photo CD's.]

Real World PhotoShop 3 ($39.95), PeachPit Press, ( has the best, down to earth, usable information of any book I've seen to date. Especially good for calibration, PhotoCD and film output.  Peachpit Press

PhotoShop in Black and White, ($18.00) PeachPit Press, covers more than just black and white. The basics of handling and creating good images are covered here. In-depth information about doing good scans.  Peachpit Press

NOTE: Most publications make the assumption that you are going to use your images for some sort of offset press system. If you are going to produce photographic film or put images on the web the rules are different. So listen carefully to the implied use the author is referring to.

Printing overview:
Printed materials are produced in what appear to be solid areas of flat color that are actually broken up by a dot pattern (halftone dots). Dot patterns come different sizes and shapes. Text can be put down with sharp, clean edges. Most processes (except inkjet) are dry or use thick offset process inks.

Images for print are laid down one "line" at a time and the number of "lines per inch" varies. Fine detail is reproduced by very small dots in lines that are very close together. The images for printing need to have a very high contrast to look "sharp" after the pattern is applied. The resolution needed for a good image is based on the number of lines per inch of the printing device. You need 1.5-2 pixels of image for every line. Your average laser printer uses between 60-100 lines per inch to create an image (not to be confused with the 400 Dots per inch of toner it puts on the paper). A Kodak ColorEdge color laser uses a 94 line screen so your image needs to be 141-188 pixels per inch to create a good image. If you have more than that it just spends lots of time throwing away information and your image is no better. If you have less you may see problems in the final print.

Every printing device has its own color and grayscale ranges. An image that looks really good on your HP Inkjet may look awful on a color laser and vice-versa. Always run tests before printing the important stuff.

Photographic overview:
Photographs are "continuous tone." Unlike printing, there is a very wide range of subtle tones in the average photo. The colors make smooth transitions form one to the next, with no sharp edges. Light is activating the chemicals on the film or paper. Photography is also a "wet" process where the film or paper is immersed in a series of "baths." Making a color change here affects the entire sheet.

Photo CD Basics
Kodak has several digital formats. PhotoCD comes in two types, Master for 35mm slides and negatives, and Pro for a higher resolution scan and/or larger film types. Both are economical ways of digitizing and storing photos. They also allow you to review your images on a TV or similar system. The main drawback to this method is in the equipment and operators at both ends. The scanning equipment has it limitations (like everything else built by man) and the expertise of the operator affects the scan at the beginning.

The equipment has been weakest at picking up details in strong highlight and shadow areas. Reports on the latest update (4050-E6 and 4050-K14) film terms, are that the new scans are "superior to Leaf scans and 95% of the time as good as drum scans." Until I check them out, a white image on a white background is not a good candidate for a PhotoCD scan. Neither is an underexposed or dark image. Images with very fine color ranges (like sunsets) or large areas of greens (forests or gardens) are very hard to capture accurately on any digital system. You may want to use a high quality film scanner like a Leaf 45 or a drum scan.

Their equipment needs to be calibrated and cleaned regularly. They should blow dust off the original but cannot use any "wet" cleaners without your authorization. Always provide some guide for the operator if you care about the quality of your images. If the operator has a negative and no reference to judge by, they will make their best GUESS at how it is supposed to look. If you know your image is a little overexposed or off color, ask them to correct it in the scan. If it looks out of focus or something is cut off, check the original under magnification. If you don't like the scan, take it back and ask them to do it over.

Photo CD Basics
Images on a PhotoCD disc (disk is for stuff like floppies, disc is for the round stuff) are accessible to any computer system that has the software to receive them: Mac, PC, UNIX, Kodak PhotoCD Player, Sega Saturn, etc.. The basic PhotoCD system is based on a UNIX workstation. When you look at the open window of the CD on your desktop you see three files:

If you change Views to View by Name the other files become visable.

As a convenience there is a set of images in a folder called "Photos" that anyone on a Mac can use without special software. These are what the design world would call "for position only" images. You use them to view the content - not the quality. The real images are compressed as a set of sizes into one file and stored inside the PHOTO_CD folder in the IMAGES folder. The basic set, referred to as the "image pack" contains five versions of the image at preset resolutions. At this writing Pro discs store the sixth (72MB ) high resolution file separately from this set. All are in the "Photo_CD" folder, with the basic image packs in the "Images" folder. The names on these file begin with IMG0 (see below) and correspond to the numbered images provided inside the jewel case cover (there may be more than one page). These images vary in size depending on the amount of compression that was acieved. Images that are black and white or contain large areas of a single color compress the most.

Now that you have the right set of images, how to best get them onto your system. Some software allows you to link the files directly. The software pulls the correct size for your output device as it needs it. Just remember to take the disc out of your drive and put it back in the box before going off to the service bureau for color prints!

Don't drag or copy the image set to your hard drive. The image set is compressed in Kodak's own coded format in YCC "color space." You need to decompress it and change the color mode before using the image. You are wasting drive space and time unless you are sharing an image and need to give the disc back.

Kodak has several utility solutions (ranging from cheap - $49 - to expensive - about $2000) for decompressing and converting the images. PhotoShop has one built- in. The difference is their ability to accurately reproduce the original colors and target them to the final use. You can get software that will take your image and, theoretically, guarantee that although it looks like hell on your screen, it will look beautiful on that large format color inkjet down the street. Most of us can't afford these high-end tools so I will explain the process in PhotoShop.

The table below shows information on most of the common film sizes.

Photo CD


Max. ppi


per color

24bit RGB

Pro 35 64 base 4000 6144 x 4096 24MB 75MB
Master 35 base 16 2048 3072 x 2048 6MB 18MB
  base 4   1024 x 1536 1.33MB 4.5M
  base   512 x 768 0.33MB 1.13MB
  4/base   256 x 384 96K 288K
  16/base   128 x 192 26K 72K
Pro120 (6x4.5) 64 base   4096 x 3072 12MB 36MB
  16 base   2048 x 1536 3MB 9MB
Pro120 (6x6) 64 base   4096 x 4096 16MB 48MB
  16 base   2048 x 2048 4MB 12MB
Pro120 (6x7) 64 base   4096 x 4780 18.67MB 56MB
  16 base   2048 x 2390 4.67MB 14MB
Pro120 (6x9) 64 base   4096 x 6144 24MB 72MB
  16 base   2048 x 3072 12MB 36MB
Pro 4x5 64 base 4000 5230 x 4096 20.43MB 61.3MB
  16 base   2048 x 2615 5.1MB 15.3MB

Do you have enough RAM? A Base 16 image will need 54MB of RAM (real or virtual for PhotoShop) to decompress AND 5 or 10MB of System memory to manage during the process. Make sure that the system and application software was installed with the option to access PhotoCD images. The Custom button in the installer will get you to a list of the installation options. Reinstall all the CD options if you have doubts.

With PhotoShop open and the CD in your drive (it should appear on your Desktop), go to the Open command on the File menu. Navigate to the CD and find the "Photo_CD" folder. Inside, open the "Images" folder and highlight any image. After clicking on OK (or Save) you will get another dialogue box.

A preview of your image should appear in the upper right corner and you have some choices to make.

f this is the first time you have opened a PhotoCD since the software was installed or you have several film types, you need to set the Source. Click on Image Info to see how the image was scanned. A color negative may say "Color Reversal" and 052/-9 SPD 000 #00, etc. you need to match this information in Source. Open Source and choose the closest match. The Device drop-down menu should read "Kodak PhotoCD." If you or someone in your company bought extra transform modules you may have a long list of choices. If not "PhotoCD Color Negative", "Universal Ektachrome", and "Universal Kodachrome" are your choices. Each has a read-out at the bottom that you can match to the information in Image Info.

Next set the Destination. DON'T use RGB. Unless you have a setting for your exact device and you don't need to do much work on the image, use PhotoShop CIELAB. For some unknown reason using RGB at this stage will not only make your file bigger, it will give it a red cast. You can convert it to RGB in PhotoShop later. Also choose the File Size - preferably one at or larger than the final size you need. For a full size web page you need a Base image. For a spot in your genealogy program you may need only a 4/Base image. The Kodak references are very helpful in determining which size is appropriate for a particular job. If you want to make another slide or negative, or the cover of a printed brochure, you will need the Base 16 or larger. If the image was rotated during the scanning process (used if it will be displayed directly from the disc on a TV or other device) there will be an option to rotate it during the decompression. This will add to the total time it takes so do some tests.

Now you have an image. Save it to your disk - if you close it at this stage it will NOT prompt you to Save unless you make some change to the image. Take a look at the color and brightness. Most PCD images are overly bright. If you correct the brightness while in CIELAB, no changes to color or clarity will occur in the process. If there is a big color cast this is the place to change it. For specifics refer to the Real World PhotoShop chapters.

Most of the PhotoShop tools you need are available in LAB, some are only available in RGB. Check the manual for differences in how they operate within each color space. Don't convert any image to CMYK until you are totally done with it and you know what the proper setting are. Never convert from CMYK to RGB and back to CMYK! Every conversion destroys color information you can't get back.

Sandra Ragan © 1999

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