CHROMiX

CMYK +RGB profile

im again trying to go where boldly no man has gone before… it feels :wink:

i am more experienced now… and built a nice linear linearization. ink limits set. everything looks good. total ink to 270. trying to build a profile for fineart prints, not proofing. on a difficult pear paper, as the shadows block easily and the dark blues get dull with the RGB profile.

like i said… lin look lin… then i set up a .tiff in monaco profile with 270 ink lim. and when printing the swatches they appear mostly dark and muddy.
the limit is ok. nothing smears or leaks… but the colors are mostly darker then monaco expects…

is that “normal” ??

when i print and scan an RGB swatch im used to almost get matching colors?

thnx everybody

and attached is the result of the first ICC profile… as you see the blue channel is off and the grayaxis is blue, too

any ideas of what to change? i would like to learn from the mistakes :wink:

:unamused: :unamused: :unamused: :blush: :unamused: :unamused:

http://www.4shared.com/photo/BZxKecbs/profile-test.html

You don’t mention what printer you are using and what measurement instrument you are using to measure your patches? I just wanted to confirm that the printer and paper you are using are capable of getting the saturation and range that you are expecting. Matte papers will tend to plug up in the shadows more than a gloss or luster. There are some measurement instruments (SpectroScan tables) that do a better job of drawing out more shadow detail in a profile than others.

Having a dark profiling target is not unusual. You would be printing the target without color management, so you’re getting pretty much raw color after the basic linearization. That’s normal for the color to be strong and dark (compared to what you might see on screen.)

You should certainly be able to get a more well-behaved profile that does not have strong gray color shifts and blue gradients that are choppy. Something seems to be wrong there.

patrick thanx for your prompt answer.

im using a Z3200ps and a DTP20… i didnt know this was important.

i was just surprised to see the mesuarments pop up in the profiler next to the “should be” colors beeing mostly brighter.

the paper is hahnemhle pearl paper. and i know from the RGB profil what it is capable of.
my RGB profile is excellent - colorwise and from the gradients… it just puts down too much ink only in the blue channel that dulls the pearl effect.

thats why i wanted to use a RIP to see if i can get more out of the paper by limiting the violett channel mainly in the CMYKRGB.

i changed the GCR settings and got a better gray balance now. and im sure i can work on the blue, too.

how would you build the black for a CMYK profile like this with a printer that has 3 blacks/grays ?.. i want him to only use black and gray for neutrals…

working with monacco

We usually need to use some other colors in order to make truly neutral black & white prints, but you can certainly reduce the other colors by building a profile with an aggressive amount of GCR. You would want to watch that your saturated colors don’t get muddied and that your highlights are not speckled while using high GCR.

Steve wrote a good article on black builds a while back:
colorwiki.com/wiki/The_Color_Key

If you are truly wanting to use a 7 or 8 channel profile, you will be at the mercy of the RIP. There are very few RIPs that handle multi-channel profiling. You’ll probably need to do a lot of experimenting to see just what the RIP is capable of - and where it fails.

thank you patrick. this was indeed the best article i read so far. it points out everything very clear and understandable.

still it mainly referrs to presses (of course). and you also say

and

this is what steve says when talking about…“if you dont have an epson with light gray then…” BUT what IF you have that epson? thats my question!

why is there NOTHING about profiling a RIP for a CMYK plus printer? there are so many out there now? HP was one of the first. been doin it for over 5 years!!..

when using the RGB driver HP only uses llk, lk and K for neutrals. so the “internal” profile must know what to do without speckling :wink:

so you have anything to read about that, too? the perfect build for an inkjet profile ? thank you

Since you’re working with an HP 3200 with light grays, you would not normally see a problem with speckling. If you do, you can start your black at about 20 - 40% so that everything lighter than that gets printed with only CMY inks. Then use a medium-high GCR setting or whatever setting you say you changed to to get better results. These are pretty standard settings for inkjet profiles.

I am a little unsure about whether you are making a true 6-channel multi-channel profile or making a CMYK profile. I assume you are working with a CMYK profile since the true multi-channel profiles are not very commonly supported by most RIPs.
colorwiki.com/wiki/Color_Man … re_6_color

In that case, the light grays are added in by the RIP by its own internal smarts that we don’t have access to. When making a CMYK profile, we only have access to be able to change those four channels - and the software (RIP in this case) handles the behind-the-scenes decisions about when to use the light gray and when to use normal gray, etc. Obviously when going through the driver with RGB profiles you have even less control and the driver does more behind the scenes.

True multichannel profiles, where you adjust each ink channel individually, require special RIPs, your target image would have to be in the “.eps” format to handle the multiple colors,… it’s just not very common for people to have all those components together.

thanks patrick.

yes. i am doing a true multi channel profile. with wasatch you just dont have influence on the light channels. (l magenta and llK and lK) but i did a lin for c, M, Y, K, R, G, Violett.

then with monaco i build the profile and have a choice for the black gen and the spotcolors through curves and hue and sat sliders.

im getting different opinions right now about the K build.

if i have a black start of 0 and end of 100… does that mean neutrals are only printed with K (llk, lk, k whatever the RIP thinks). cuz i was told that CMYK will always use CMY as well to neutralize?

Black starting at 0 and ending at 100 means that black is available to use throughout the spectrum. It does not mean that black will be used exclusively. So yes, CMY will be in use to neutralize at all times.

thank you patrick.

to me a serious disadvantage of a RIP compared to the printer driver i never knew about!

the printer driver uses only the 4 black/gray inks when i send equal RGB values. so totally neutral or at least metemerism free pictures are the result.

if the RIP doesnt… it is def. a point against using a RIP for fineArt printing.

besides that so far i have tried dozens of different black gens and am getting close to smooth gradients. still having a bump in the green. but i think it is more a problem of the swatch i am able to print and the ICC program then my black gen.

thanks for helping