Photo CD: The Amiga Enters the Age of Digital Photography



     There is an old adage which maintains that a picture is worth a thousand words. If recent

developments in the image processing industry are any indication however, it's time we changed that

pronouncement to a picture is worth several megabytes. Since its introduction to the photographic

and desktop publishing markets in 1992, the Kodak Photo CD format has significantly changed the

means by which images are both manipulated and stored. Whether you are involved in amateur or

professional photography, electronic publishing or multimedia, Photo CD (or PCD) is destined to

change the way you look at visual images.

     A typical Photo CD is comprised of representations of 35 mm negatives or transparencies which

are processed by transfer bureaus or photofinishing labs. Each image is scanned using custom

technology which digitally encodes the original picture as a series of 12-bit RGB (red, green, blue)

values. PCD discs are then mastered on CD-recordable drives, resulting in the production of one of

the special gold discs which have come to characterize the PCD format. While these discs are identical

to the aluminum-based platters used in the manufacturing of audio compact discs and CD-ROMs,

Kodak maintains that the reflective gold layer used with PCDs is both more durable and less

susceptible to the effects of oxidation. When combined with a scratch-resistant outer coating, the

company claims PCDs have an estimated life expectancy of about 100 years.

     Images contained on PCDs are kept in five resolutions and are stored in an area known to as

an Image Pac. Each Image Pac in turn appears as a file in the CD0:PHOTO_CD\IMAGES disc directory

listing. Individual Image Pacs maintain all the information needed to produce an image at any one of

the five designated Photo CD resolutions. These specify the vertical and horizontal dimensions of the

encoded image and are referred to as Base/16 (128x192), Base/4 (256x284), Base (512x768), 4Base

(1024x1536), and 16Base (2048x3072). A special Pro Photo CD 64Base format stored in the Image Pac

Extension (IPE) is also offered, yielding a resolution of 4096x6144. The latter three image sizes address

the needs of professionals, and use a lossless Huffman encoding system to compress their resulting

file size. The need for this compression becomes quite apparent when you consider that an

uncompressed 16Base image typically weighs in at about 18 MB. After the compression technique is

applied, the resulting Image Pacs are reduced to anywhere between 1/3 to 1/6 of their original size.

     

You Ought to be in Pictures



     Because of the fact that Photo CDs are capable of storing roughly 100 images (or four 24-

exposure rolls of film) in a range of display resolutions, the advantages of their use are readily

apparent. For those involved in image archiving and analysis, the ability to save photographs to such

a compact medium reduces the demand for storage space. Commercial prepress and electronic

publishing services have also discovered that PCDs eliminate tedious image transfer procedures by

allowing photographers to submit their work in a machine-readable format.

     But one doesn't have to be involved in commercial imaging to discover the benefits of this

technology. With nearly 60 billion photographs taken in an average year, it's obvious that visual

imagery is a preoccupation for virtually everyone. The main advantage of the PCD format is that it

provides an option for permanently storing high-resolution digital images. You simply drop off your

roll of film at a photofinishing outlet and request that a Photo CD be produced containing the pictures

found on your film. The charge for mastering a Photo CD will vary considerably, but you can expect

to pay roughly $1 per image. Keep in mind that the expense is not the only variable you need to take

into consideration. Because of the fact that Photo CD technology is relatively new, be sure to consult

with others in order to find a photofinisher which has a reputation for quality film to PCD image

transfers.



The Paparazzi Amiga



     Taking advantage of the Photo CD format is an opportunity which is available to virtually

anyone with an XA-compatible multisession CD-ROM drive and appropriate software. Amiga users can

relish in the fact that a wide variety of applications currently offer support for the PCD format.

Available in both the commercial and public domain arenas, these programs offer capabilities ranging

anywhere from sophisticated Photo CD manipulation to simple format conversion utilities. 

PhotoWorX



     Distributed in North America by both Interworks and Spectronics, Corporate Media's

PhotoworX ($199) has quickly garnered a reputation as being the preeminent Amiga Photo CD

processing package. Adopting a graphical interface popularized by Kodak's own PhotoEdge software,

PhotoworX will operate on any Amiga equipped with revision 2.04 of the operating system and a

minimum of 2 MB of RAM. Video support is offered for the native Amiga HAM and HAM8 display

modes, with additional drivers available for the Picasso II, Retina, EGS and DCTV graphics adaptors.

Enclosed with the program disk is a well-documented user reference guide and a Photo CD containing

25 sample images. I took the opportunity to test PhotoworX on an A3000 series machine equipped

with 8 MB of RAM and a Picasso II 24-bit graphics card.

     Transferring the PhotoworX software onto your hard drive is an intuitive process which makes

use of Commodore's standard Installer program. Once you have responded to all the configuration

options, the program may be started by simply double-clicking on its icon. You then personalize your

PhotoworX installation with the pertinent registration information, customize the program settings and

you're ready to begin. Photo CD images may then be retrieved in one of two fashions. The first method

involves selecting PCD files from a standard ASL requester, using a thumbnail preview to associate

the nondescript "IMGxxxx.PCD" names with their corresponding images. Having loaded the picture,

the program then allows you to render the image either to a window on the current screen, or to a

specified custom screen. Options are available to set the size, number of colours, shading, and

dithering method to be used to display the photo. These selections are restricted somewhat by the

amount of free memory, but the program has provisions for full support of virtual memory solutions

like GigaMem. This becomes a welcome addition when you consider the fact that a 16Base 2048x3072

24-bit picture requires almost 19 MB of contiguous memory for decoding.

     An alternative method for viewing and manipulating Photo CD images under PhotoworX is

through the contact sheet. Just like a series of proofs developed by a photographer, these slides serve

to represent the pictures found on the CD. The dimensions, number of colours, shading technique,

and number of columns used to display these slides are all configurable and may be set as desired.

Double-clicking on any one of the preview images loads up the corresponding picture and renders it

according to the designated display mode parameters. By using the 'view' menu option, it becomes

possible to examine the picture in full-screen mode and take advantage of several of the most popular

24-bit graphics cards.

     Apart from the extensive image viewing options at your disposal, PhotoworX offers a bevy of

processing features for transforming PCD pictures. Images may not only be printed and exported to

a variety of IFF formats, but also flipped along their X and Y axes, rotated in 90 increments, and

colour-adjusted according to their brightness, contrast, gamma and RGB attributes. Additional options

are offered for smoothening and sharpening the image, as well as producing a negative. It is also

possible to define an area of the picture to enlarge, reduce or cut a portion of the image. These

functions will undoubtedly prove to be particularly valuable to many users, and set PhotoworX apart

from its competition. Regrettably, the current release does not make provisions for AREXX support,

an option which is becoming increasingly essential for image processing and manipulation.



AsimPhoto



     Like PhotoworX, the AsimPhoto utility bundled as part of Asimware's AsimCDFS package ($89)

allows you to convert PCD images by selecting them from a file listing or through a pictorial directory

containing greyscale miniatures of the pictures. Requiring revision 2.04 of the operating system or

greater and a minimum of 512k of available memory, AsimPhoto provides a simple approach to

converting PCD pictures. Following installation of the suite of applications included with the CD-ROM

file system, you simply double click on the AsimPhoto icon and you are ready to explore the world of

Photo CDs. For those users equipped with a Picasso II or EGS graphics adaptor, it is possible to view

pictures as full-screen 24-bit images.

     While AsimPhoto is decidedly more spartan when compared to PhotoworX, it does offer an

AREXX port for converting PCD images to their 24-bit IFF equivalents. This feature is especially

helpful for situations in which you wish to perform batch conversions through programs like ADPro,

Image FX or Imagemaster. At the present time, the greatest liability with AsimPhoto is the fact that

it does not offer support for the 4Base and 16Base PCD formats. This will prove to be of little concern

for most users, but is a need which should definitely be addressed in future revisions. Video display

mode support for the HAM and HAM8 modes is also sorely needed.

     In order to address a number of these concerns, Asimware has indicated that it will be

releasing a more robust Photo CD solution which will be marketed under the name Photo CD Manager.

The preliminary version that I received at the time of this writing was designed specifically to cater to

the needs of CD32, A1200 and A4000 users. Photo CD Manager ($59) not only adds support for

displaying pictorial directories in colour, but allows for images to be rendered to the 262,144 colour

HAM8 modes available under AGA series platforms. Additional features allow you to compose slide

show presentations of Photo CD images, using a variety of wipes, fades and transitions. This should

prove to be good news for those interested in conducting multimedia presentations.



Public Domain Solutions



     While PhotoworX and AsimPhoto offer Photo CD-specific applications which will accommodate

the needs of most users, those with more modest demands may want to take a look at some freely

distributable alternatives. All of these programs are widely available on local BBS systems and the

Aminet FTP archives. HPCDtoPPM by Ingo Wilken is an Amiga version of the original UNIX program

by Hadmut Danisch. This utility is designed to convert Photo CD images to Postscript and Portable

Pixmap (PPM) file formats. A number of variables are offered for modifying the attributes of the

resulting images, including dithering and scaling. Quite powerful, but definitely not for the uninitiated.

     Originally released as part of XETEC's CDX CD-ROM file system, PCDtoIFF is a simple

command line utility which allows one to convert Photo CD images to their 24-bit IFF equivalents. The

resulting files may then be displayed using packages such as Image FX, ADPro or Viewtek by Thomas

Krehbiel. Options are available to specify the desired PCD resolutions, file names and depths of the

resulting IFF images. PCDtoIFF is a derivative of the HPCDtoPPM program, but will prove to be

straightforward for those comfortable working within the CLI environment.

     PCDIFX by Gunnar Niclas offers a PCD extension to users of Image FX. You simply copy the

program into the modules/loaders area of the installation, and you now have the capability of reading

images in the PCD file format. Accredited to 'BAZZ', OpalPCD is a similar program available for users

of the Opalvision card from Centaur.



The Final Analysis



     Despite the fact that Photo CD technology has only recently become available to microcomputer

users, the potential applications of this development are enormous. Whether you foresee Photo CDs

as becoming an integral part of your image processing needs, or you are simply inclined to use this

format for entertainment purposes, Photo CDs offer an economical way of bringing digital photography

to the desktop. For those looking for a professional-quality Photo CD processing package, look no

further than PhotoworX. It is not only extremely versatile and easy to use, but also offers a wide range

of image manipulation functions. With the addition of AREXX support, it will become an essential tool

for anyone interested in using Photo CDs in their productions and publications. AsimPhoto on the

other hand, offers a cost-effective solution which is merely one component in the series of CD-ROM

utilities bundled with AsimCDFS. Also watch for Photo CD Manager, an inexpensive AGA-specific

presentation program which promises to be just what you'll need for showing off your latest product

or the snapshots from your recent vacation.



Asimware Innovations

101 Country Club Drive

Hamilton, Ontario

CANADA

L8K 5W4

(905) 578-4916

(905) 578-3966 (FAX)



Interworks

43191 Camino Casillas, Suite B2469

Temecula, CA 92592

(909) 699-8120



Spectronics International USA

34 E. Main Street #23

Champaign, IL 61820

(217) 352-0061

(217) 352-0063 (FAX)



Xetec

2804 Arnold Rd.

Salina, KS 67401

(913) 827-0685

