I want to make a decorative glass panels on walls on our kitchen (the one between the hanging kitchen cabinets and the tabletop). The company I am negotiating right now uses UV coating as a printing method. I can’t say for sure whether it’s printing directly on glass or at the white glossy film glued to it.
Problem is, the image we’re intending to print failed two coloring tests already. Red color becomes pink and the amount of colors drops considerably (details gets lost in the dark areas).
First coloring test was from CMYK image with color profile for US matter paper, saved to TIFF with ZIP compression.
Second coloring test was from RGB image (same CMYK as above but converted to screen sRGB) saved to JPEG level 9 baseline.
I don’t even know whether they use CMYK color model or what because their “designer” don’t understand my questions.
Is there anything I must account for when preparing the images for UV printing? Color profile, amount of colors, color mode?
The process is as follows: three separate raster images gets placed into the CorelDRAW layout and I assume this CorelDRAW layout gets printed directly to the printing device.
Will their CorelDRAW template (I can ask for it) help us in preparing the design which will not get colors screwed or it’s a problem of the source raster image?
Will reducing the magenta color channel by some amount help? My main problem is red color becoming pink (I admit it was pink initially but it becomes much more pink in the resulting piece of glass).
We finally decided that we’ll print anyway and got our glass panels delivered. Colors were screwed up completely, all yellow was gone and overall the picture became darker. It looks like someone put a pale blue color filter over the picture. And it was nowhere close to what we got on the coloring test.
My best guess is that in this kind of printing the glass determines what colors the output will have. In our case obviously we got some pretty thick glass with blue hue so the image came up as it did. I will remember to always ask the people at printing company to make coloring test with exactly the same kind of glass as the final product.
However, my original question is still open: how one should prepare the design document for printing on a white film behind a glass?
In this case you have a verey specific non standard problem.
The ideal thing would be that the provider give you his color profile… But I don’t think he have it. u_u
One thing that can help in this case, is to print this sample with this same provider in the real material http://www.otake.com.mx/Apuntes/RGB-CMYK/Pruebas/1-RGB.png and use thoose colors as a reference.
In this case I would recomend working with your standard prepress configurations (Northamerica, Japan, Europe) but using RGB colors.
After printing the test, use it to adjust individual colors in your work.
This can be a pain, but will give you predictable resoults.
P.S. Save 2 copies of your work, the original and the modified.
Oh, and yes, yhou should do some preliminar tests on the same kind of glass and conditions you have in the final product.