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KODAK PROFESSIONAL: Technical Information Bulletin

Kodak Photo CD Disc: Transferring and Viewing Images
 
 

Contents

Updated 19 June 2003

 

How do I transfer images?

It's easy! Bring a completed roll of unprocessed film to a service provider (also known as a transfer site). The service provider may have the equipment to do both the film processing and the image transfer. If not, they may process the film and send the negatives or slides elsewhere to have the disc made, or they may send the film elsewhere for processing and transfer the images to the disc themselves. The images from your original film are scanned onto a Photo CD Disc using a Kodak Photo CD Imaging Workstation (PIW).

When you pick up your order, you will receive (1) the disc in a jewel case, (2) an index print showing thumbnail-sized pictures of all the images on the disc, (3) your original film.

 

What is the cost?

All service providers in the United States, and most of those outside the U.S., are independent companies who establish their own prices. Kodak does not establish pricing for transfer services.

Prices vary by provider, scan format, and level of service (for example, consumer versus professional). Consumer scan prices can range from US $0.50 to US $4.00 per image. Some service providers offer value-added services such as film cleaning, custom scanning, etc. Professional labs may offer scans using the advanced Kodak Professional PCD Film Scanner 4045, as well as additional services such as encryption, watermarking, and advanced adjustments.

Usually it is easier, and therefore more cost-effective, for the service provider to transfer the images to the disc immediately after film processing (before the negative film has been cut into shorter strips or the slide film placed into individual slide mounts.) It may be less expensive to use a service provider who does both film processing and image transfers. Shop around to find the most suitable blend of services and prices.

Note: You do not need to have prints made if you only want the Photo CD Disc.

 

What types of film can be transferred?

 

Negative or slide

High-quality scans are possible from either negative film or slide film. Negative film is easier to scan.  

APS

Advanced Photo System (APS) film can be transferred to a Photo CD Disc. Contact one of the service providers listed below for information.

APS cameras do not crop images. The camera encodes the film so automatic photographic printers "know" which format the photographer wants. The Kodak Professional PCD Imaging Workstation equipped with the APS Film Gate transfers all the image content to the digital file. Any size format can be created with this data.

United States

Canada

Elsewhere

Advanced Digital Imaging, Inc. (ADI)
101 Remington Street
Fort Collins, CO 80524
Telephone: 1-800-888-3686

Colortron Photo Services Ltd.
175 Barton Street East
Stoney Creek, Ontario L8E 2K3
Telephone: 1-905-560-2222

Contact Kodak
in your country

Digix Imaging
1450 Research Blvd.
Suite 200
Rockville, MD 20850-6101
Telephone: 1-800-434-4491

Wolf Camera
3036 Commerce Way
Hapeville, GA 30354
Telephone: 1-404-751-1235

 

Processed

Processed negatives or slides (both color and black-and-white) can also be transferred to a disc. Find a service provider who does the work themselves or can arrange for it on your behalf.

 

Large format

Pictures on larger film formats, such as 120 or 4 x 5 sheet film, can be transferred onto a Photo CD Pro Master Disc by using the Kodak Professional PCD Film Scanner 4045. Films can be scanned at 6144 by 4096 pixel resolution, depending on the image format.

A Photo CD Pro Master Disc may hold as few as 25 pictures because the Image Pac File for each picture can optionally contain six resolutions: Base/16 to 64 Base. If only five resolutions are written, a Pro Master Disc could contain up to 100 images. Each Image Pac File on a Photo CD Master Disc contains only 5 resolutions -- the highest resolution, 6K x 4K (64 Base), is not available. See Resolution Information (TIB7058) for more information.

 

Image quality

Will the transfer quality always be the same?

A hallmark of the Photo CD system is color and exposure control. The system produces optimumly scanned images the first time, every time, despite inconsistencies in the original image. In some instances, however, a skilled PIW operator can improve the results. Additionally, how individual service providers maintain their equipment and handle your original film can vary greatly. The same is true of photofinishers who use the same equipment, but the quality of the prints you receive may be different.

Are PCD Film Scanners calibrated?
Kodak Professional PCD Film Scanners are color calibrated to a defined set of aims using targets that are more tightly produced than other generally available calibration targets. In addition, the "dark" and "gain" levels are verified and adjusted every time the scanner is started and after every 2 hours of use to help ensure consistent results. If changes are made to the film scanner, Kodak service personnel can calibrate the systems.

Do film scanners produce the same image quality as drum scanners?

The answer depends on the type of film being scanned and how the scanned image will be used. There are relative limitations in the current density range of the PCD Film Scanner but not in the color-encoding metric.

In reversal film (slide) images with high densities, you will see a difference in high-quality reproductions if the information in those dark densities is critical. In many situations, however, if the image on the Photo CD Disc is processed correctly, it produces the same result in the final printing as an image made using a drum scanner.

There are no practical density limitations when scanning color negative film because of its inherent lower density range. In addition, the Kodak technology in the system helps ensure consistent results because it contains important information pertaining to the unique tone scale and reproduction properties of the film, information that many other scanning systems do not include.

You should always use a good conversion to CMYK rather than using the defaults in some applications.

What is Scene Balance Algorithm?
The scene balance algorithm (SBA) is included with every Kodak Professional PCD Imaging Workstation. The service provider may use the SBA to correct camera-exposure variations caused by the picture-taker. Optical printers automatically use a similar technique when making prints from negatives.
Note: Professional images are assumed to be correctly exposed or may have scene content that is atypical for the algorithm. Ask the service provider to reduce this SBA correction or turn it off entirely.

 

Tips

Can my pictures appear in a particular order?
Yes. Organize your pictures before submitting them to your service provider. Specify your needs to your service provider when you submit your film. This may affect the cost of the transfer.

Does a multi-session disc contain fewer images than a single-session disc?
Yes. There is a certain amount of overhead (roughly 16 to 18 megabytes) associated with each session on the disc. This information takes the space of 3 to 4 images.

I have a single-session CD-ROM reader so I must put all my images onto a disc at one time. I recently sent my service provider enough negatives and slides to fill a single disc, but they put my negatives on one disc and my slides on another. Now I have wasted space on each disc that I cannot fill. How can I prevent this in the future?

Because single-session CD-ROM readers are used less frequently, your service provider probably assumed that you have a multi-session reader and that you could fill the discs at a later date. When you submit future orders, specify your needs and always mention that you have a single-session CD-ROM reader.

Do Service Providers need special instructions?
Do you want the service provider to perform additional manual corrections to your images rather than relying solely on the automatic scene balance algorithm? (See previous question). Additional corrections may reduce the lab's productivity and may increase the cost of a transfer. However, the extra care taken in scanning an image may be worth the extra cost. For scanning reversal images, typically the lab will use the Universal Film Terms to retain the look of the original transparency.

Can I photograph a gray card?
The service provider can use a gray card to obtain a good initial balance to use with your order. Be sure to:

  • Expose a gray card properly.

  • Use the same exposure conditions for ALL of your exposures.

  • Process the film with consistency.

Instruct the service provider to turn off the SBA and prescan your gray card. The service provider can adjust the gray card to be 79, 156, 137 in PhotoYCC to reproduce the gray as an ideal neutral. If you want your images slightly warmer or cooler, ask the service provider to bias the gray card balance and then hold this balance for the remainder of your order. The same correction will be made to each image. Keep in mind that you may not always want a neutral to be exactly neutral.

 

How are the images compressed?

Several techniques are used to compress the images onto a Photo CD Disc. All of the techniques have been carefully analyzed to produce visually lossless results. Briefly, the image is converted to a luminance-chrominance (luma-chroma) storage metric called PhotoYCC. The chroma information (CC) is then subsampled because there is less need for color detail information since almost all of the detail is retained by the luma channel (Y). A hierarchy of resolutions is created and stored on the disc, with the higher resolutions stored as residual or detail maps.

The other reductions in file size are realized with these residuals. These residuals are reduced in size by quantization (a visually lossless process of grouping together similar information) and by Huffmann encoding, which is numerically lossless. The amount of the compression step is controllable on the latest Kodak Professional PCD Imaging Workstation 4220.

 

Viewing your images

Can I view my images on my computer monitor?
Yes. You must have a CD-ROM XA drive and an imaging software package compatible with Photo CD Discs. Your imaging software must be capable of reading the .pcd file format.

My disc contains files other than my images. How can I view them?
The additional files on a Photo CD Disc (in addition to the Image Pacs) provide image file information to Photo CD Players, CD-I Players and computer systems. These files contain very detailed binary information and are not useful to the user.

I burned photos on a CD-R but they won't play.
Photo CD Players were designed to read image files in the .pcd format only. They do not recognize image file formats written by common authoring packages (for example, jpeg, tiff, bmp). Photo CD Players can also read audio files.

I make my own CDs but my DVD player won't play them. Where can I buy a Kodak Photo CD Player?
The Kodak Photo CD Player is discontinued. Most DVD players do not play image files.You can write image files in several different file formats to a blank CD-R, but a true Photo CD Disc is written in the .pcd format. The software to create .pcd files is provided only to Kodak service providers. You can write your images to a blank CD-R using the Video CD file format. Video CD version 2.0 supports high-resolution still images but not all authoring software packages support this Video CD option, and not all DVD players are compatible with CD-R media.

Kodak, Kodak Professional, and Photo CD are trademarks of Eastman Kodak Company.

TIB7057

Technical Information Bulletins provide information of limited or specific application. Responsibility for judging the applicability of the information for a specific use rests with the end user.