Tuesday, July 4, 2023

Abandoned Early Digital Technology: the Kodak Photo CD

Background


The great Eastman Kodak Company was an early pioneer in the technology and science behind digital imaging. Kodak scientists and mathematicians developed many of the early patents pertaining to digital imaging chips, data processing, and color management. The Department of Defense funded some of this early work. The popular press and photo "experts" in internet fantasy-land love to curse at Kodak and say how it totally missed the digital revolution. As usual, most of them have an agenda and the story is more complicated.

Kodak's managers, scientists, and engineers were fully aware of how digital imaging would eventually destroy their immense profit machine. Kodak made money from film production and selling supplies to photo-finishing companies around the world. These were high-margin disposable supplies that needed constant replenishing. Digital was totally different. It was based on the manufacture of cameras and peripherals (memory cards and software), a different economic model from Kodak's. 


Three Photo CDs from 1995. Note the handy index sheets.

What is a Photo CD?


During the transition period of the 1990s, Kodak tried to bridge both worlds with their Photo CD. From Wikipedia

Photo CD is a system designed by Kodak for digitizing and saving photos onto a CD. Launched in 1991, the discs were designed to hold nearly 100 high quality images, scanned prints and slides using special proprietary encoding. Photo CDs are defined in the Beige Book and conform to the CD-ROM XA and CD-i Bridge specifications as well. They were intended to play on CD-i players, Photo CD players (Apple's PowerCD for example), and any computer with a suitable software (LaserSoft Imaging's SilverFast DC or HDR for example).

You can read more details on this site.

To buy a Photo CD, you first had Kodak (or select laboratories) develop your film. Then they scanned your frames with proprietary Kodak scanners to a compact disk (CD). 

From Linotype-Hell Company technical note:

The Kodak Photo CD scanner uses a stationary tri-linear array (three linear arrays with a R,G, or B filter) of 2048 elements. It is designed exclusively for 35mm film. During scanning, the film is moved parallel to the long dimension of the frame. This results in a scanned data file of 2048 by 3072 pixels in R, G, and B per frame of 35mm film. Before this data is quantized for storage, several transformations are made to optimize the encoding of the data for various applications and to achieve data compression.

The primary consumer application for Photo CD is television display. Kodak therefore has chosen to refer to the TV display resolution as the Base image. This resolution is achieved by averaging 16 pixels in the original high resolution 16 Base image to create each single pixel at Base resolution. This averaging is done in a two-step process so that an intermediate resolution HDTV image (4 Base) is also available. In addition, since TV uses luminance/chrominance data, the scanner RGB data is mathematically transformed into a single luminance and two chrominance components before processing. Kodak identifies the particular luminance and chrominance that they use as PhotoYCCTM (or YCC for short).


Kodak PCD-860 player (by permission from an eBay listing by 68ra-53)

Kodak designed the system to allow customers to see their photographs on a television screen. Kodak sold several Photo CD playback readers that you connected to your television. But American analog NTSC (National Television Standards Committee) televisions in the 1990s had poor (OK miserable) color and dynamic range. To make the photographs look good on a television screen, Kodak's software expanded the color and dynamic range. I am not sure how the CDs were encoded to play back correctly on PAL or SECAM televisions. Possibly, the playback units for those markets did some software processing internally. 

I do not know if these players will work on current Digital Terrestrial Television (DTT) units that use the ATSC (Advanced Television Systems Committee) standards. 


Reading Photo CD Files


Many software packages, like Ifranview, will still open the .PCD files on the PhotoCD. But images often look washed out because of the exaggerated dynamic range. I think Kodak planned to offer a software to open the files on 1990s computers, but I have not been able to find a copy. Maybe this software was never offered to the public. Kodak recommended that applications use a Lookup Table (LUT) after converting the PhotoYCC data from the Photo CD into RGB. 

The problem lies in the fact that most modern programs do not have access to these Kodak lookup tables. Most software companies have long discontinued their packages that opened Photo CD files and properly corrected the color and dynamic range. LaserSoft no longer sells their SilverFast PhotoCD. pcdMagic may be the only currently-marketed software that runs on contemporary computers.  

An alternative: a Photrio reader wrote that Digital Light & Color Picture Window Pro 7 correctly opened the Photo CD format. Version 7 is now a free package. But only the 32-bit Windows Version 7 opens the Photo CD. I downloaded it onto a 64-bit computer running Windows 7 Pro, and Picture Window opened correctly. 

A minor issue: Picture Window needs the index files that are on the Photo CD. If you downloaded just the .PCD files to a hard drive, I think you cannot access them. Therefore, you need the original CD as well as a CD reader. If your computer does not have a CD drive, you must find/buy a portable unit or need to revive an older computer. (Hint: do not discard your legacy computers; you never know when you might need some of the old hardware or software). 


Skopelos, Greece


Hora (main town), Skopelos, Greece (Kodachrome 25, Leica M3, 50mm Summicron lens)
Hora, Skopelos (90mm ƒ/2.8 Tele-Elmarit lens)
How does my garden grow? Skopelos town (135mm ƒ/4 Tele-Elmarit lens)
My croissant is too small; Skopelos


Skiathos



Hangin' out in the sun, Skiathos
Waiting for departure, Hora, Skiathos
Kastro, Malaria Beach, Skiathos

The Kastro was the medieval fortified town on the very northern tip of Skiathos. It was settled in the 1300s when the islanders fled from the raids of Turkish pirates.

Morning in Skiathos



Mainland, Attica



Abandoned loading dock for minerals, Grammatikó (near Marathonas) (50mm Summicron, polarizer)



Summary


My experience with the Photo CD process was mixed. You can see that on many of these frames, the colors are exaggerated or a bit off. Some have a subtle color cast. For some Kodachrome rolls, the files on the CD were very good quality. But other CDs had poor exposures and colors. I think the Kodak automated scanner may have set color and gain for the whole roll based on the first slide. But if that slide was poorly exposed, and no technician inspected the process, the .PCD file for that first frame ended up looking good, but the rest of the roll looked poor.

Dark Kodachrome slides did not scan well. The dark areas were noisy and had a purple color cast. It is possible that the Picture Window Pro 7 software did not correct the colors quite right. And it is possible that being designed as a display media for NTSC televisions, the colors will never be "correct". I could do more adjustments with Photoshop, but that ends up taking a lot of time. It may be better to just scan from scratch with a film scanner.

I expect that C-41 negative film, such as Gold 100, would have transferred more successfully on the Kodak CD system. 

I did not use Photo-CD scanning after the late-1990s. And I never bought one of the viewing units for the television. Still, it was a clever interim technology. Eastman Kodak deserved credit for trying to integrate traditional film with the digital future.

2 comments:

Mike said...

Very nice overview of that pioneering tech. Also a good reminder that our image archives are dependent on complicated technology that is not always going to be available.

Suzassippi said...

I enjoyed the report, even if some of it was unfamiliar to me. I did get a few rolls of film developed on a CD file a couple of times when it was new.