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Hector Zombo
01-18-2005, 12:55 PM
When viewing in Lightwave ..... previews, reders and such, is there a way to see the colors as they realy are for print. Example: with photoshop there is a way to view images as you would see them in video, or web or print, but what about lightwave?

I find a dramatic color shift when reders are imported into photoshop.

Thanks Hector Zombo

kopperdrake
01-18-2005, 03:14 PM
Nope. Lightwave works in RGB and saves as RGB. It wouldn't be part of a 3D program's remit to work in any other colour space and I wouldn't expect to see it. So the way to do it is as you say, take it into Photoshop. If your colours are changing so dramatically, are your colours set up properly in Photoshop? When are they changing? As soon as you load them? After you've converted to CMYK? When you're printing?

etobiason
01-19-2005, 12:10 PM
RGB is true color, and has a wider color gamut than CMYK. Even if a photographer shoots something, and has the transparency scanned, that scan will have to be converted to CMYK for printing. So LW isn't any different, really, the final output must be converted.

The conversion process is tricky at times. There are some commercially available printers out there (Canon makes good photo printers) that convert your RGB images for you when it prints. Often these printers have more than four inks (you know CMYK stands for the four inks Cyan, Magenta, Yellow, and blacK). My printer has six inks, adding another Magenta and Cyan (which they call Photo Magenta and Photo Cyan, lighter versions of the base color) which extends the printable gamut.

Photoshop has display settings, where it may try to emulate on your monitor (which is RGB of course) what an image will look like on paper (CMYK). If this isn't set up properly, what you see on the screen can be drastically different than what you get when you print.

One thing I typically do when converting files is use "Image:Mode:Convert to Profile..." instead of "Image:Mode:CMYK Color". Convert to Profile gives you more control, you can choose different CMYK color conversion models (or set up your own) and preview how the image will look when converted before you make your choice. Even so, after conversion, be prepared to color shift certain colors and bump up saturation.

-e

Darttman
01-19-2005, 12:39 PM
When it comes to print many people use monitor calibrators. If you do alot of print work a regular old crt instead of a lcd will give more "truer" colors to base off of for print purposes. If only a small percentage of your work is done for print you can probably get by doing it by the seat of your pants. On the other hand if your are doing large scale work for print and print is your main type of work then I would be serious about color matching all your harware.
Many people dont think about it when the print out a couple bubblejet photos. I worked with a service bureau (pre-print service) and learned alot about he print world. Get friendly with a local service bureau so you can get some tests done to refine your work. You will pull alot of hair out if your client is a stickler for detail!

Bottom line talk to the local service bureaus or the printer you will be using and let them guide you through it. It probablly won't hurt to do some reading on the subject as there are alot of books and web sites to help. It is up to you to get the color corrected when you are working with LW.


Good Luck!

kopperdrake
01-19-2005, 01:05 PM
To clarify, even RGB isn't true colour - just a small portion of what we can actually see.

For mission-critical colours in an image I tend to use a Process Colour Guide - Agfa used to make one and Chronicle Books also produced one (by Michael and Pat Rogondino).

To use it, take your RGB file into Photoshop and convert it to CMYK using whichever technique suits you. I have my Photoshop set up for my specific monitor and Europe Prepress Defaults in Color Settings (unless I'm working with digital photos, in which case I use a Custom setup based on sRGB as opposed to AdobeRGB as that's what Canon cameras shoot in by default). Anyway, once you have your converted CMYK image, you just use the colour picker to take samples of important colours and then look the value you have up in this Process Colour Guise, which will give you a fairly good idea of how that colour will print, assuming it'll be printed in the 4-colour process :) A good example is the sky in a rendering - you want a good blue, you know what you want as you've seen it in a photo. Well, use the Process Colour Guide to look up the nearest value blue as a CMYK value, and then compare that to yours in Photoshop. If they don't match then you're going to have to mask off the sky and tweak the CMYK channels in the Curves or Levels panels. It's a pain, but after a while some of it will become second nature. Also getting a decent printer will help you proof your own stuff at your end to a certain level. It'll never be cock-on accurate to a print from a lithographic printers, but it'll be much better than relying on your screen. Saying this, even lithographic printing companies are all slightly different. A really professional one may even be able to give you their settings so you can stick them into Photoshop, but I have never in my lifetime come across a printing company that could do that for me :) And we're talking over 10 years producing 3D renders for print! The worst colour was Cadbury's chocolate brown...looked great on screen but when it came to printing in CMYK you were always a hair's breadth from baby-poop brown!

I personally prefer Epson printers for colour proofing, using a Stylus Photo 2100 7-colour A3+ printer here. Their prints are less vibrant than a Canon's, but to me they seem a lot closer to the colours you'll get from the 4-colour process print that your brochure will be printed in at the end of the day.

Just my tuppence-worth :)

Dunk

J. Stuart J.
01-24-2005, 01:07 AM
I would be nice if Newtek would at least implement color profiles in Viper or with in the render preview. That way there would be fewer suprises for the novice.

What I've always wished for was a virtural sensitometer or light meter, that would allow me to select say an array of 1 to 5 pixels. Lightwave would then render those pixels and return the averange in RGB and the converstion values for a defined ICC Profiles. Maybe even allow us to define several point in layout that would provide such feed back as you adjust the scene. This would help in seting up renders for print reproduction, similar to using the zone system in photography to capture a reproduceable range of color on film.

J. Stuart J.
Prepress/Color Control Specialist

kopperdrake
01-24-2005, 02:34 AM
That's a good idea :) I wonder if anyone could come up with a plugin that could extrapolate this information from a limited region render? The only problem is that it could only give you an RGB value, so you'd still be stuck with what it's going to look like in CMYK. As Lightwave can't possibly know what kind of post-production you're going to put it through after it's rendered to get it to CMYK then it may not prove that useful, save to do away with having to send the limited region to Photoshop, or similar, to find out the CYK value there.

J. Stuart J.
01-29-2005, 03:46 PM
Well there is LittleCMS; http://www.littlecms.com, perhap someone skilled in plug-in writer could make use of it. Its lienced under the MIT lience, and appears at first glance thatit could be utilized to convert from RGB to CYMK, and back again.

Perhap some intrested plug-in, developer could create a plug-it that would work similar to Adobe Photoshop's "Proof Colors" Function, pick a input profile, an a output profile, and the plug-in would displays the converted data back through the input or a third display profile. I would think this could at least be created as a pixel filter, and would give you a bacic soft proofing ability.

It wouldn't and perhap never would be perfect, but perhap better then nothing, expecially for those not trained in color for print reproduction and prepress.

J. Stuart J.