Re: It's The White Stupid
Re: It's The White Stupid
- Subject: Re: It's The White Stupid
- From: Louis Servedio-Morales <email@hidden>
- Date: Fri, 05 Oct 2012 11:03:38 -0400
Hi Terry- We have left off Houston! Using the IDEAlliance spreadsheet calculator proved to be a problem at the exact point you predicted, and that is, importing the CGATS file into i1Profiler. I felt I tried everything but no success. Unfortunately, I'm living dangerously and have migrated to Mountain Lion and no longer have access to MeasureTool so I couldn't try the re-save trick. Did manage to save out the i1Profiler GraCol Data set and edit what I thought was the white point values and successfully round trip it back to i1Profiler then build a profile. I then moved on to trying the "Profile White Point" adjustment in the profile setting of the build profile workflow using the canned GraCol data. Which btw has 5 more measured values (1622) then those generated by the calculator (1617). I used ColorThink Pro to analyze other settings from the standard GraCol 2006 1v2 profile. Settings like black start (33) and total ink (320). This method has given me the results I'm most happy with so far. Especially since the white point is as entered according to ColorThink. Also soft proofing and hard proofing appear to have the correct "blue" influence of the new white point within the image.
My issues now are as follows:
1. When proofing on standard white paper (e.g. L95 a0 b-2) the white simulation is slightly magenta blue. Should I be tweaking my measured final substrate white I entered when building the profile till I get something more neutral or at least just blue? I'm thinking I've got some OBA voodoo going on or is that a bad practice. BTW I am viewing proofs in an up to date 50D 2009 light booth.
2. Do I now need to create a customized proofing control bar to print along side my image or should I continue to print the original control strip?
3. Is their an accepted naming convention for my final CMYK separations file using this "Home-brewed" GraCol profile? And or a naming convention for the profile itself?
BTW when I used "non-UV measurement" I did mean I INCLUDED the UV. I guess I should've said "non-UVcut measurement" ;)
thanks again,
Louis
On Oct 4, 2012, at 3:00 PM, Terence Wyse wrote:
> Questions:
>
> 1. So am I entering a new white value sampled from the final destination actual printing substrate (i.e. McCoy Silk) or the white of the proofing paper? I'm thinking it's the former.
You should already have a profile of your proofing paper with it's know white point.
You want to measure the substrate you're trying to match and use that to create a new GRACoL profile.
An alternative to using the calculator Mike mentioned is to simply use a profile editor and edit the white point of a standard GRACoL and save that as a new profile. This is how I always used to do before the IDEAlliance spreadsheet calculator came along....I've tested it both ways and the results are identical.
>
> 2. I used the newer i1Pro2 and the i1profiler OBC workflow to make my inkjet profile. Measurement mode was: Dual scan (M0, M1, M2 and OBC). And yes, I did end up entering UV correction values to correct for OBAs. But since my final profile has a white point of L97 a2 b-7 I'm guess it used a non-UV measurement for this value. Do you agree and should I use a non-UV measurement for the "New Paper WHite Value" of the McCoy substrate?
To say "non-UV measurement" always confuses me. This implies you excluded the UV from the measurements but I suspect that you mean the opposite...that you INCLUDED the UV component into your measurements (M0, M1) as opposed to EXcluding UV (M2).
All I'm saying is that you should measure the McCoy Silk the EXACT SAME WAY you measured your proofing paper. I've never used the OBC function so I can't advise on that.....just saying if you used M1 (or whatever) to arrive at your proofing paper profile, you should measure the McCoy Silk exactly the same way.
>
> 3. I am understanding that after creating a new CGATS file with the new "substrate modified data" I can then use it in i1Profiler and create a "relative" GraCol profile that I then simulate printing with. Is this correct?
Yep. You could ALSO try creating a new GRACoL profile from the dataset provided with i1Profiler....there's a point in the workflow (Profile Settings?) where you can enter a different paper white point than what's provided in the original dataset.
>
> 4. Is i1Profile good with seven decimal point values? The sample CGATS file had two decimal point values and the calculator is spitting out seven places. I'm really not savvy enough in ExCel to round values off but I'm sure I can figure it out if need be.
I've no idea!....but it's easy enough to tell Excel to round to 2 decimal places (or whatever). You're more likely to have problems with stupid stuff like the CGATS header data causing issues with i1Profiler. I have problems with this all the time in i1Profiler.....CGATS data that can easily be read my PM5 Measure Tool can't be read in i1Profiler. Solution is to open the data set in Measure Tool and simply re-save it....then i1Profiler seems to like it.
Classic problem for me is creating/exporting a CGATS "color list" in ColorThinkPro to use as a dataset...and i1Profiler refuses to digest it. A trip into Measure Tool to re-save the data and then back into i1Profiler does the trick....I've looked at the files before/after and have no clue what i1Profiler doesn't like about the original file but Measure Tool seems to deal with it just fine. Go figure.....one of MANY frustrations (still) with i1Profiler.
Terry
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