Single Strike/Double Strike ink restricions?

[M.A.C.]

Experiment for yourself and see. You can compare icc's made through each method for gamut comparisons to verify your tests.

Just wanted to chime in that I have been doing lots of testing with both density and Lch readings, and have had much better results as far as gamut size with the Lch.

[jcuads]

The gamut of a given profile is made possible by the colorants or strength of the colorants available. Keeping channel limits as high as the media allows and controlling the multiple ink levels within the Ink Limits provide the strongest foundation. e.g. if magenta at 100% reads 1.4 then Cyan does not need to be much higher than say 1.5, beyond that it will be cut down in the profiling process anyway. In this case to keep the K at 1.2 and the Y at 1.2 would provide a bit more than enough ink for the profiling process. For instance if the the Cyan was cut back to 1.1 then the M & Y will also be cut in the profiling process thus clipping or reducing gamut. Channel limits are not that critical in the sense of precise measurements. The important thing is to measure the values of the Cyan and Magenta then adopt to the lower reading of the 2 at 100% to avoid over inking. The K and Y end up a couple of tenths lower than the C and M. In conclusion whether to use Chroma or density readings is not as important to me as keeping reasonable balance while providing a little more than the necessary colorants to create the profile. With the HP 5500 the Cyan usually stays at 100% setting the path for the myk where as the Mimaki the Magenta stays at 100% instead.

[eye4clr]

Dude, you're popping off without any first hand knowledge of the differences. Ink restrictions by chroma will save you 15-35% ink without loosing any gamut. I know it's hard to break out of the density perspective. But I know from personal experience that if you test it you'll see what i'm talking about.

I have no interest in arguing with you in a pissing contest. I'm offering a method that is proven to be more effective. Not only by myself but by many others who are far smarter and more experienced than i am.

[jcuads]

Where is this wasted ink? I Don't see it anywhere, does it evaporate? When I do Ink restrictions using Advance mode I then cut back on any excessive loading if necessary and use black compensation when needed. Not to argue, but I've been around the block a time or two and do realize there are great minds out there. Still, I feel most of the time the simple answer is the correct one. Getting overly technical would negate the need to even create an ICC profile. In the process of creating the profile the software can only compress or cut back it can't put back ink previously restricted.

[jcuads]

eye4clr, I've taken your advice to explore ink restrictions by chroma values. Please read on and advice if so inclined. With Mimaki SS2 ink @ 720x720 and the medias used I've never experience a decline in chroma values reading the Cyan and Magenta. IOW the values constantly climb even if just fractionally. However now that I also own and operate an HP 5500 Dye, I get values in the cyan and occasionally Magenta where Chroma actually starts to decrease. I've learned that a decrease in chroma value indicates basically a change in color and restriction should take place right before change. However I'm not certain if chroma has to go negative or to the point where the increase is fractionally small. I think I understand using L measurements for black as I restrict at the point before change in direction. Yellow set to most neutral CMY value as you describe (wildcard) or I may use density around 1.2 depending on density of Cyan and Magenta after established by chroma.

[eye4clr]

sounds like you're spot on. Exactly where to restrict is ultimately a judgement call. I just did a profile today for a Korographics wallcover on the jv3 that needed ink restricted as much as possible. So i let the C delta e go above 1 just to satisfy an extra need for less ink to control dot gain on this thick stuff. It's really hard to see 1 or 2 delta e in rich colors, so i really didn't give up much. Normally staying at or just below 1 delta e is the way to go.

But like a lot of this color stuff it can be a judgement call at times when you're dealing with poorly performing system.

[jcuads]

eye4clr, It is amazing that Onyx 7.1 doesn't mention or change the defaults on ink limits on the ICC options! Again, taking your advice and setting to 280 on the ICC options creates a considerable ink savings and an improvement in overall tonality. I noticed on the 6.5 media guide a screenshot showing the ink limit in the ICC options set to 260, which now I realize can also work well, however they make no mention or suggestion to do so. In summary... after setting ink restrictions as discussed in the previous thread, the only time one should limit the ink prior to the ICC is when having issues that may effect the printing of the patches then finally apply the 260 - 320 ink limit at options build time. Correct? Thanks again, JC

[M.A.C.]

" In summary... after setting ink restrictions as discussed in the previous thread, the only time one should limit the ink prior to the ICC is when having issues that may effect the printing of the patches then finally apply the 260 - 320 ink limit at options build time. Correct? Thanks again, JC"


Eye4clr suggests doing your restricitons, ignoring multichannel ink limits, and then doing your total ink limit (280ish) to handle your blacks.

I tried profiling the same media with and without multichannel ink limits, and didn't get any improved gamut size when doing the profile without the multichannel ink limits. I continue applying multi channel ink limits because of this. It makes me feel a little safer in case I screwed up my restrictions somehow.

But yea, Eye4clr is an advocate of bypassing multichannel limits.

[M.A.C.]

"I noticed on the 6.5 media guide a screenshot showing the ink limit in the ICC options set to 260, which now I realize can also work well, however they make no mention or suggestion to do so."

Things like these are what bother me the most about Onyx, and it isn't close. I sound like a broken record, but their lack of instruction and documentation is amazing.

[jcuads]

I profiled a POSTER COLOR MATTE for the HP 5500 where I had to multi- channel limit in order to be able to print patches. The limits where something like 1.8 to 2 throughout the 7 steps, consequently I had to set the black compensation to 4.5 to bring back the gradients. I profiled leaving the limit to 400% at build time and it actually looks okay, however I'm thinking that the 280 principle would still apply because as stated by eye4clr the limit at ICC options basically controls how much CMY will lay on top of K and at some point usually beyond 280, there is no visual difference. I will rebuild this profile at 280 later to verify. JC.