#DPI Question
20 messages in this thread
Working on a joint project with an associate, I have come across a situation
that I cannot solve:
Both users running R3 and the same .prj file, we can find no differences in the
individual 3ds.set files other than Vibrant display variables.
After rendering Tif output null at 2048×1536, my image becomes that size at 72
DPI. This is using the image info option in PhotoShop. I modem this file to the
service bureau for print and it goes directly into the Fiery Downloader with no
resizing needed.
My associate renders a different view of the same project, and the Fiery
Downloader cannot handle the file because it is too big. He is using the exact
same resolution. Looking at his image in PhotoStyler at the service bureau
reveals that the image is 2048 inches x 1536 inches at 1 DPI. This is why the
Downloader won't take his file without resizing in PS. We have found that any
action in PS changes our gamma and a darker image is output. Direct to the
Fiery Downloader creates great results.
Here is the real mystery. In PhotoShop, the image info tells us that it is
2048×1536 pixels at 72 DPI. The same image in PhotoStyler tells us that it is
2048 inches x 1536 inches at 1 DPI.
We have not had this problem before and figured it must be in 3ds.set
somewhere, but cannot find an associated switch. Any feedback on why the
different outputs would be greatly appreciated.
Mike Swinford and Dan Spomer
Mike,
<< we can find no differences in the individual 3ds.set files…. >>
I'm at a loss. The only 3ds.set parameter that is even remotely related to TIFF
is the IMAGE-COMPRESSION [ON|OFF] og 55 of the installation manual. Are both of
you using/not using compression when creating the tiff?
I don't have either of the 2 products (photoshop/photostyler).
jonas[adesk]
Hi Jonas, Neither of us are using compression option in the TIF file. We
checked this first. Still having problems with the files. After modifying the
prj at Dans machine, I brought it home and did a render with the same
results..2048 inx 1536in at 1 DPI.
Could it be Sunspots??
Mike
Mike:
Try a common paint program like the shareware Paint Shop Pro. This would at
least prove that 3ds is not the culprit and it would be free until you felt
Paint Shop Pro was worth the registration. (It is by the way)
Bob
Robert-
Where do I find Paint Shop Pro? Here on CIS??
Mike:
For Paint Shop Pro use Go GRAPHSUP and download PSP.ZIP. FWIW I think the
program is included on the CD which accompanies "Inside 3D Studio".
Bob
Thanks for the info Bob. I just bought the book and have not opened it yet.
I'll check it out.
Mike
As I recall, you posted this same message awhile back. You say that PhotoShop
says the image is 2048×1536 at 72 DPI while PhotoStyler says it's 2048×1536 at
1 DPI. Sounds like one of those two packages is mistaken. I just saved four
renderings of the same image as TIFF color/compressed, color/uncompressed,
mono/compressed, and mono/uncompressed, and then loaded them into Altamira
Composer, Picture Publisher, and Photo Finish. All reported them correctly as
512×486 resolution.
I once had PhotoStyler, but am no longer using it. The darkening you report is,
I suspect, because of their Kodak "Precision" color system. As near as I could
figure from playing around with it, the Kodak system makes certain assumptions
regarding gamma and adjusts the incoming images, whether you want it to or not.
I believe this is the same with the Kodak PhotoCD images, that contain embedded
gamma values. I spent more time than I wanted attempted to nullify the effect
in PhotoStyler. Unfortunately, their documentation avoids mentioning "gamma" in
connection with the Kodak color system. Probably someone in the marketing dept.
at Kodak felt it would be over the heads of the customers. <g>
– Jack
Hi Jack-
I do not recall posting this problem before, as this is the first time I have
seen it. I did mis-post it on another forum last week though. Photostyler is
not my personal choice of image manipulation programs, I use Photoshop. My
service bureau uses Photostyler for scaling though. As I said in my original
message, the best output is going directly to the Fiery Downloader program and
straight to the Canon A1 BubbleJet. This cannot happen when PhotoStyler says it
is such a large image.
Guess I should get my bureau to buy PhotoShop!
The biggy is for you I guess….Why does the same .prj file produce different
outputs on different machines? Sounds unlikely that 3ds could do such a thing.
There is not that many output options. We have shared many projects before with
no problems, then all of a sudden this shows up.
I believe the heart of this matter lies in the service bureau set-up. They are
rather new………Just wanted to make sure we were not overlooking the obvious
in 3ds.
Again, Thanks for the great support!!
Mike
I don't think the .prj file is producing different results. If you render a
single frame of the same scene from the same .prj file on two different
computers, and the load the two images into the _same_ image-processing
software, you should get the same resolution for both images. (To troubleshot
[troubleshoot] this, you need to narrow the process down to a single variable.)
If, given this process, the two images are reported to have different
resolutions, then you're not going through the exact same steps when rendering
the images on the two different machines. For example, one operator might be
rendering from the 3D Editor, and another from the Keyframer.
We'd be interested in hearing from you when you track down the solution to this
puzzle.
– J
*
whether you want it to or not.
*
The KPCMS will only make corrections if you choose a precision transform file.
As for making the corrections, if you have your gamma correctly calibrated and
the PTs for your input/output devices, everything will work with a 99.5%
accuracy. Here is how it works:
The KPCMS will assume that you have a perfect 1.8 gamma monitor and will target
your PTs to the specified monitor (there are only two generic PTs for monitors,
for EBU and P22 phosphors). Photostyler gamma correction will provide you with
that 1.8 gamma if you know the real gamma values of your monitor (you can check
your monitor gamma with styler, although I recommend another external software,
because the pattern in styler is not very good). Once you have the "perfect"
display, the rest is easy. A hardware calibration probe will make a perfect job
in the monitor calibration if you are going to print.
One more thing about KPCMS, we and many other people have tested, work and save
a few dozens of hundred$ thanks to KPCMS.
For sure, Aldus should think about hiring you for writing the docs for version
3 😉 Styler docs doesn't make a good job about making the inners of KPCMS
straight to the user. Maybe Microsoft will make a better job than Aldus
explaining how it works in Chicago's docs. IMHO, it will be better for
everyone, including the Altamira guys, to make their software to work with
Chicago's color correction technology. Specially since Apple, Sun and most of
the big pre-press players have announced support (Apple System 7.5's QuickDraw
GX gets this technology as part of the MacOS).
ana /krazy images
Thanks for the explanation, Ana. Unfortunately, I no longer have PhotoStyler to
try it out on. The problem was, every image I created in other programs
(including 3ds and Composer) displayed too dark in PhotoStyler when I had my
gamma set to 1.8. Ultimately, I had to set the display gamma to somewhere
around 3.5 to get the correct results.
– J
Ana:
Which monitor did you get with your XL? Does your monitor seem dim in
comparison to others? Even with the brightness cranked up my monitor is dark.
I find it nearly impossible to do accurate color correction of images which I
wish to print or put to video.
Bob
I didn't get any, Robert! Another monitor and we are going to put them one on
top another 🙂 We already had big displays (Idek) for our old boxes, so that
was an element that stayed with us. Sorry I am not being able to help. I think
that Gus got a DEC monitor with his system and he is very happy with it (a 17"
model maybe?)
ana /krazy images
It sounds as if Photostyler is off with the info it's giving you. Are
both of the files the same size in megs? Have you tried the file info in 3ds to
check the number of pixels? If the number of pixels are the same, then the
files should be the same size when the dpi matches. 2048 x 1536 inches at 1 dpi
is the same as 2048 x 1536 pixels at 72 dpi (1" at 72 dpi = 72" at 1 dpi). I
don't know Photostyler, but have been using Photoshop for 3 years now in a
prepress shop in San Francisco, and am more than happy to help out with it or
any other dpi questions you might have.
JW
Jason- The files are exactly the same size in megs. I realized after going
through some old threads that the DPI equations were the same, although stated
differently in the two programs.
The big question is why my machine rendering the exact same .prj (only camera
view was changed) produced a file that went straight to the Downloader (It will
only take a max of 11×17 inches) and Dans had to be rescaled because it was so
"big".
Time to drop this now, I do not believe the problem lies in 3ds at all. But
still confuses us.
Thanks for the kind offer to help in the future….does your shop do hardcopy
for hire? I am still looking for a good service bureau who understands 3ds and
is willing to make it right. Another forum member suggested Digital Pond in the
Bay area, you know them? I am in Nashville (the printing capital of the U.S.)
and all the great hardcopy devices are in-house and not for hire.
Mike
Yes, we do output 3m Rainbow Proofs, 3m Matchprints, and Dupont Waterproofs,
but we tend to be a bit more expensive then the typical service bureau. We are
a full prepress facility with scanning, stripping, and full design
capabilities. Our targetted market is in the high-end advertising agencies,
which is why our prices tend to be higher. As for 3d Studio, my company (who
pays all my bills) does not use it. Instead they use (I hate to say it here in
the Autodesk Forum, but here goes….) TDI. 3d Studio is what I do on the side
for a hobby/extra cash in my spare time (what little time I can find!) Someone
a while back mentioned a service bureau (I think in New York) that does 3m
Rainbow Proofs for real cheap, hopefully that person will see this and help
out. But, if you're still interested, let me know, and I could probably e-mail
you some prices. And, of course, if you have any more questions about prepress,
I'm more than happy to help.
JW
Jason, I would be interested in your pricing. Please drop in E-mail or Fax me
at 615-883-6510.
Thanks, Mike
Mike:
3DS doesn't set a DPI in the TIF file format. Obviously Photoshop sees this and
assumes it's default DPI. Photostyler makes on assumptions. If you call up the
image in Photoshop, Photostyler, or any other paint package, change the dpi to
what the Fiery (spelling?) can do, and resave the image then everything will be
ok.
Simple.
Robert- Changing the scale\DPI settings is the work around we have been doing.
Unfortunately PhotoStyler puts the Gamma Whammy on the image, and there goes
WYSIWYG.