#Hi-Res,24bit hard copy?
9 messages in this thread
I have a need to produce high-resolution, 24-bit color still images, and am
considering purchasing a software package such as 3D Studio to create a
digital file and then use a service bureau to produce 35mm transparencies.
One hang-up is that the digital file will be about 4MB in size. What is
the best way to get this to a service bureau? Is there software available
which will split the file into several parts so that floppies can be used?
Can compression techniques such as JPEG be used to reduce the file size to
1.44 MB without seriously compromising quality?
I would appreciate comments from anyone who has thoughts about this.
Thanks, Ken
File compression is always an issue when you need to move large files
around. Sometimes the service bureau can help out with suggestions. PKZIP
is a standard utility for compressing files down. Then programs like
FASTBACK, DOS's BACKUP, etc can cut a file up across multiple diskettes.
One option you might consider is a removable cartridge hard drive. They
typically come in 40 or 80 Mb (drives and cartridges I believe, similar to
the 7.2 vs. 1.4 Mb floppies). Many service bureaus have such drives
available but of course you'd want to check with ones in your area. Don't
have any experience with them yet, but I should be getting a Syquest 40Mb
drive tomorrow or the next day for similar reasons.
I usually use PKZip and then use ZIP2EXE to make it a self-extracting EXE
file. But I think most service bureaus can PKUnzip a file. I have gotten as
high as 97% compression on 24Bit uncompressed TIFs.
-MM
Thanks for your comments about using PKZIP. I have used this for standard
data files, but assumed that it would not be effective for graphics after
reading an article in PC Magazine on image compression (April 28, 1992,
p.338) which states "Data-compression utilities … aren't very effective
for full-color images.", and "the 2:1 ratio offered by lossless compression
techniques just doesn't cut it when you need to … send even one such file
down to a network printer."
Any comments on the position presented in this article?
KLK
Kenneth,
I just realized that in my last message I recommended a "type" backup. Of
course I meant to say "tape" backup. I hate those tapos<g>.
Dennis Bragg
Kenneth,
I read somewhere that you can generally use JPEG to compress 8:1 without
discernible (or displeasing artifacts). That should get many hi-res images
down to manageable size (over several floppies). Right now I use just pkzip
and then dos backup – many of the service bureaus near me have 40mb syquest
cartridges which might be the way to go. I haven't done that because most
of my stuff is broadcast animation and I don't know of a good compression
method for that yet – JPEG does not work well with animations, only stills.
Martin
I used to think lossy compression would not be an exceptable way of
getting my files to a managable size, but I have since changed my mind.
I once had the task of compressing four 13mb targa files for transport
to a service bureau for slide processing(these are 4 views of the houses
done by my co-workers and I at The Pyros Partnership which can be seen on
the new 3D studio Siggraph demo tape).
I used Image Alchemy, a wonderful command line file conversion program.
I converted the files into the JPEG format and brought each one down to
under an incredible 500k each.
To make things simple I copied these to diskette and wrote a batch to
copy and uncompress these images back to there size of approx. 50mb total.
I tested my batch and printed these images on a Mitsubishi 300dpi dye-sub
for comparison to the original file prints. I saw almost 0% loss of
quality.
Depending on the particular image being compressed the loss may be more
apparent, I haven't had time to test files of that size since. But I've
gained a new respect for JPEG and lossy compression.
You may consider getting a type backup. We use a Colorado Memory Systems
Jumbo 250 that cost about $350. We can get up to 250 MB of files on one
tape. The tapes costs about $20 – $25 each. They use a pretty standardized
format, so any service bureau should be able to read them. Much easier than
copying 20 or so floppies.
Dennis Bragg