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kdd
11-24-2014, 04:48 PM
It's been almost 15 years ago I began a journey into desktop publishing. My wife's boss assigned me the task of producing a brochure for one of his clients. I still had not mastered getting the colors I saw on my screen to translate through the printer to the paper.

I began to investigate color management. Ideally to acquire the icc profiles the print shop uses is the way to go I found out. I requested them of the shop my wife's boss used and was told "just use the Photoshop defaults". I was puzzled and explained to the layout folks what I had learned. Again, "don't worry about it" was the reply. This was in the days before most print shops used pdf files to print from.

I investigated color profiles and happened across a reference about the International Color Consortium ( http://www.color.org/ ) and their web site. I did not fully understand much of the jargon, but I was familiar with light and the colors of light both from a photographic and pigment stand point. This web site opened my eyes to a journey into color management and color workflow.

I designed business cards and a magnetic door sign for my nephew's painting business several years ago. By that time print shops were using pdf files to print from. I asked the shop owner if I needed to convert the images to CMYK before I made the pdf and was told that it didn't matter. I understood then that when you give the shop a file, they will apply the color profiles they use and your work, generally, will reproduce as you saw it on your screen.

What I have found that works for me is the icc profile that is available on the ICC web site gives me as close to perfection as I need to reproduce on paper what I see on the screen. What I did was apply this profile to all of the RGB color preferences in the graphics software, hardware profiles, and to the color profile of the computer system.

Some years back, I got into a discussion on a desktop publishing mailing list about color management with a DTP professional when I revealed my discovery. He was adamant that I was wrong, and his arguments for purchasing a $2000 color calibration system was quite convincing. With this system you could make an icc profile for all of your hardware. You would also have to paint the walls of your computer room with a (expensive) neutral grey paint and (dimly) light the room with 5000k full spectrum bulbs.

The major flaw with the latter point is that viewing your final product for "exact color" under 5000k is one thing, but when your product hits the news stands, billboards, point-of-purchase kiosks in department stores and malls, etc., the color of the light in those areas is not 5000k full spectrum lighting. The color of the light creates a cast on the subject and biases the "exact" color(s). A good example of this is Van Gogh's "Haystacks". The shadows are blue. If you take a photograph of a subject in shade, the subject will have a blue cast to it. Try it, set the white balance on your digital camera to Daylight and photograph a subject in the shade.

Even the large transparencies department stores use to hawk products are lit with florescent bulbs and not all florescent bulbs are daylight balanced. Have you ever taken a photograph under florescent lighting? Unless the bulbs are daylight balanced, the photograph usually has a green cast. Try it sometime. Set the white balance on your digital camera to Daylight and take a photograph under florescent lights.

I eventually bowed out of the conversation. I knew the results I got. I had the prints that he did not see to prove my point.

Since I obtained my profile from the ICC web site the color profile has changed. I have not procured and tested the new profile. The CMYK profile I use I acquired from a Linux distribution. The color temperature of this profile is the same 5000k temperature of the sRGB profile I use.

If you are interested in acquiring these profiles, send me a message and I will be glad to send you a copy to try for yourself.

Cheers,
Dwain

icypinkshimmer
11-25-2014, 01:48 PM
That's interesting that florescent lighting causes a slightly green hue.

kdd
11-25-2014, 04:36 PM
That's interesting that florescent lighting causes a slightly green hue.

thanks for your reply.

all light sources have a color temperature. the color temperature records differently depending on the white balance you set.

a tungsten bulb has a color temp of 3200 degrees Kelvin. That's a little over 2000 degrees F. set your camera to daylight balance, the image has a yellow cast. the image looks normal set to tungsten.

using the the opposite settings in this example, the tungsten image has a blue cast, while the daylight image looks normal.

the higher the kelvin temperature, the cooler (bluer) the light. the lower the kelvin temperature, the warmer (more red) the light. blue - cold; red - warm.

using color correction filters allows "finer" control over how warm or how cool the scene renders.

philjaeger
12-09-2014, 02:25 PM
Hey,

Since 2005 I've been using an i1 color profiler kit for many monitors, printers & scanners. The results have been consistently great for gallery shows or just hanging artwork in the home or office.

I use a 5000K solux or ecolume bulb for checking prints. The CRI (color rendering index) is close to 100, which means that its color wavelength follows natural light very closely. Most bulbs, which have a lower CRI ,have a lot of spikes in the color spectrum, which means the colors don't show accurately.

In addition to using the higher CRI bulbs I also used natural daylight, & a couple other standard bulbs just to see what the print looks like across the full spectrum of more accurate to less accurate light.

The following website has some interesting articles on lighting artwork:
http://www.solux.net/cgi-bin/tlistore/infopages/artwork.html

I also have to mention that I've read articles in the past showing that the CRI of a light might not tell the full story or be entirely accurate. In the end I have found that I should go off what my eyes tell me...:0)

kdd
12-15-2014, 03:35 PM
<snip>I use a 5000K solux or ecolume bulb for checking prints. The CRI (color rendering index) is close to 100, which means that its color wavelength follows natural light very closely. Most bulbs, which have a lower CRI ,have a lot of spikes in the color spectrum, which means the colors don't show accurately.

In addition to using the higher CRI bulbs I also used natural daylight, & a couple other standard bulbs just to see what the print looks like across the full spectrum of more accurate to less accurate light.</snip><snip>

I also have to mention that I've read articles in the past showing that the CRI of a light might not tell the full story or be entirely accurate. In the end I have found that I should go off what my eyes tell me...:0)</snip>
phil,
thanks for your reply. i just found this. there are different kinds of 5000k bulbs. what was recommended was a full spectrum 5000k bulb. i purchased mine through 1000bulbs dot com. they started around $3.50 to $4.00 each depending on the output and whether or not it was dimmable (throughout the spectrum).

what you say last is what i was getting at. most people cannot see the color cast of a light on an object. you are absolutely correct, the final way to go is what your eyes tell you. if the image of your color printer satisfies the color accuracy of what was on the monitor, then that's what it is, and, you have saved yourself the cost of a color calibrator.

in school, the professors recommended painting under the same illumination your work was going to be exhibited under. this way you could get your colors to "reproduce" correct. but what happens when the work sells and is hung in a daylight environment?

i have never used a calibrator, only the icc profiles from the color dot org web site and have never had a problem with color printing, either commercially or my own inkjet printer.

fyi, many years ago i heard of a giclee print. no one could tell me what it was. i googled it to death and one day i found out what it was and i realized i had been making giclee prints since 2000. giclee is a fancy french name for an inkjet print on fine art paper.

cheers,
dwain

philjaeger
12-15-2014, 05:39 PM
Hey Dwain,

Everything you say sounds good.

Yeah, the word giclee makes it sound like it's much more than it actually is. I used to always wonder what these incredible giclee prints were.

Yeah, also some 5000k bulbs will have a fuller spectrum (higher CRI) than others. The word "spectrum" refers to how closely the spectrum of the bulb matches the spectrum of natural light. In addition, throughout the day natural light moves between different temperatures, ~2800k to ~9000k, maybe even more than that.

If anyone does have an issue getting the correct colors I would personally recommend using some sort of color profiler. Even ten of the exact same inkjet printers may need 10 different ICC profiles, depending on their minute differences from one another.

Happy printing,
Phil