CHROMiX

Hue and saturation adjustments required for soft proofing ??

Hi all,

I do not post here very often so please excuse me if I am bending any forum rules in this post, I will try not to and also excuse any english mistakes, I am french speaking.

I am experiencing an issue where I cannot get my Eizo CG275 to soft proof my prints unless I manually adjust Hue and saturation.

Here is my setup :

  • An Eizo CG275W calibrated to 6500K, 120cd, 2.2gamma, gray balance using colornavigator.

  • An IPF8400 printer and Hahnemhle papers. Profiles are created through a X-rite i1Pro2 using the following details : 3000patches / M0 measurements / Standard D50 illuminant / A to b and b to a large tables 16bits / Profile v2 / profile white point default.

  • A just Normlicht Color communicator 2 D50 with the illuminance being adjusted through color communicator to match monitor brightness.

  • Printing does not happen through RIP but through the canon driver.

I would suspect only some small white point adjustments to be required with such a setup to obtain satisfying soft proofing.

But I have to manually adjust Cyan hue to -32 and red saturation to 13 on the eizo to match my prints being viewed in the light booth. Adjusting white point does not allow me to correct for both the cyan and red deviations at the same time.

Now my problem is : I just don’t know how to tell my clients to soft proof at home with their calibrated monitor.

I was thinking about manually adjusting inks lay down on the ipf through the driver preferences to match as close as possible a 6500k calibrated monitor but I am afraid of gamut reduction and furthermore I would need to re-profile all my papers again.

Any thoughts, good advice or possible solution by anyone ?

Thanks in advance.

Laurent

Hi Laurent,

This is a good question; thanks for bringing it up.
While the numbers seem large, the -32 cyan and +13 red are not necessarily that dramatic. Minus 32 cyan on the hue would actually tend to reduce red, and then adding the +13 red sat puts some of the red saturation back in. To my eyes, this ends up having an overall slight increase in the saturation of reds, but it seems like a small increase. Is that what you are seeing?

Note that these manual adjustments will change the way your reds appear on screen and leave other colors (including the white point) unaffected.

You mention soft-proofing. Are you using Photoshop or something else to soft proof? Going to View > Proof Setup > Custom and viewing your image through your printer profile there? If you click on the preview checkbox, you should get a very accurate soft-proof. This is a necessary additional step besides merely calibrating the display. Depending on the paper white color of the Hahnemuhle papers, you may need to use the emulate paper white checkbox to view the image on screen as it will appear on paper.

I just bring that up because it might be that a proper soft proof procedure may eliminate the need for any manual adjustments. You might get a good match without using manual adjustments, if you create a new target and aim for a lower white point like 6300 or 6100. Have you tried that yet?

Just a thought, but why haven’t you tried to calibrate and profile your screen to the same WP as that which your viewing booth is producing? I’m writing this on my iphone, so can’t check my own version of ColorNav (I use a CG242W, i1display3/i1d3, 3880, i1pro2, etc.) but I’m pretty sure there is an option to measure your viewing booth colour temp/WP and use that measurement (Yxy) as the WP setting for your screen so that you don’t have to waste your time and effort trying to match the colours by eye. That way you’re assured of having the correct and matching WP setting for your screen.

Also, you must make sure to actually measure the viewing booth illuminant and use that in your i1Profiler settings as the source illuminant in your profile creation. Otherwise, it’s doubtful your soft proof will be accurate as you’re telling your profiling app you’re viewing the prints under a D50 source but in actual fact, you’re not, you’re viewing your prints under the (definitely NOT D50) viewing booth’s source illuminant. Regardless if it uses LED or CCFL backlight, its spectrum will be VERY spikey, with large gaps in the spectrum, not the beautifully smooth and full and even spectrum which D50 describes.

I’ve never used a viewing booth as I made my own print viewing light source using some Solux 4700K bulbs in a custom light fitting I created. Using this or natural daylight, my soft proofs match very accurately.

Something to also think about is your BP. I set mine to 0.5cdm or even 0.6cdm (depending on the paper I’m using at the time), as my WP is set to 120cdm, giving me about a 200:1 - 240:1 contrast range. There’s no use having your screen produce blacks of 0.1 or 0.05cdm as although you’ll have a HUGE contrast range, no print could ever come anywhere near such a huge range of contrast.

Just curious, why do you use a 3000 patch target? Be careful as i1Profiler has a bug where if one selects the “wrong” number of patches, they could end up with almost zero neutral and near-neutral patches in their target. Also, since a number of Hahnemuhle papers use FWA/OBA, you should make use of the dual-illuminant properties of the i1pro2. Since your printer is likely very linear, you might find that 1000-1500 patches or maybe up to about 2000 will be more than sufficient. It’s also quite likely that there could be minimal or no visible benefit or improvement in the profile created with 3000 patches, compared to a profile created with just 1200-1500 patches.

Just a few things to think about. Also, I’ve found that the rather inexpensive i1d3 produces smoother, more accurate and more pleasing profiles than either the i1pro Rev. B or i1pro2 is able to produce. Maybe you could borrow one from someone to try it out or just grab one new from eBay or somewhere, for about US$250 or so, brand-new in sealed packaging. Definitely worth the minor outlay compared to the cost of the rest of your setup IMHO.

PLease keep us informed as to how you’re progressing and if any of mine or Pat’s suggestions prove helpful and/or useful.

Thanks a lot for both replies.

Yes of course. And after doing so I get extremely accurate soft-proofing capabilities.

It is the reason I am confused. My technique is the following :

After a complete profiling / calibration process with the given details in the original post,

  • I open up a test image under PS,
  • Select soft proofing with the correct paper and rendering intent
  • Display the print in the light booth
  • Open up the monitor preferences in parallel
  • Adjust manually color temp of the monitor to fine-tune the print-to-screen matching.

Doing this last step, I was only expecting some minor white point adjustments to be required, the rest (to my humble thoughts) would be taken care of by the profiling.

Well no. Otherwise I could tell the photographers that use my printing service to just calibrate their monitor to a white point x,y, 120cd, 2.2 gamma. But now I also need to tell them : ‘heads up, you’ll still get issues in the cyan range’.

There must be something wrong in my color-chain !?

Concerning this specific matter, there is a whole geekish discussion well above my level of color-science, (i’ll try to find back the post and link it) telling that to soft proof an illuminant of 5000K, the closest results are obtained by setting up the monitor to approx. 6500k. (something dealing with the difference between reflected and emitted light perception by the humain brain), which is what I see : Apart from the cyan shift, all the colours are correctly reproduced with a white point of about 6300K while the light booth is at 5002K.

Do you have any more details or a link ?

I am experiencing this problem even with 100% RAG papers with 0 OBA’s.

That is my next step, trying another profiling system. Probably an iSis.

To conclude :

Any thoughts on the impact of adjusting ink lay down in the printer driver on the overall gamut ? I will give it a try, profile a paper and compare the resulting profile with the original under color think pro and post my results.

Actually, with a 5000K viewing booth, Quato’s research has found that a WP setting of about 5800K for the screen is about the closest match, typically 6500K would be much to cool. Also, why would you think that your Eizo screen should be able to soft proof a viewing booth automatically, without measuring said viewing booth’s own illuminant colour temp? You have to remember that your printer profiles are most likely all created with the assumption the user is viewing the prints under D50 source, which is VERY different from a 5000K source. More specifically, your viewing booth will have an extremely spikey spectrum with many frequencies completely absent from its source illuminant, as do all viewing booths not using Solux bulbs, so that will also be part of the reason for the mismatch you’re experiencing.

To get your screen, booth and soft proofs to match, you really do need to physically measure the booth illuminant and specify that measured illuminant in your printer profiles. Otherwise, what you’re doing is telling your system that the prints will be viewed under a D50 source, but that isn’t what you’re actually doing. You’re viewing your prints under a 5000K source, NOT D50, and you haven’t informed any part of your profiling setup that you’re using the 5000K source and not D50, as you’ve specified in your print profiles.

Essentially you must put your actual physically measured source illuminant into your printer profile and go from there, otherwise you could be messing about for a very long time with attempting to match apples to oranges, if you know what I mean.

As for your ink laydown, if you aren’t using a rip, you can’t alter individual ink channels, only the overall density or amount of ink being put onto the paper. I often do this with my 3880 printer as many papers I use can easily handle an extra 10-15% more ink without any ill effects and it certainly does increase the printer/paper gamut. Obviously the opposite will occur if you remove ink, as opposed to adding more ink. Better to start a new thread in the printer section for this question I think. :smiley:

As for the target patch count bug in i1profiler, I can’t give you a link as I’m using my iphone to write this reply but maybe Pat or someone could provide the link. Or it might even be in the list of vids on ColorThink’s YouTube channel. If not, I’ll try to elaborate further once I get onto a computer with an actual keyboard :wink:

Heres a link to a slide showing a list of patch counts in i1Profiler for RGB. Depending on how many patches you choose, you can either have a lot of near-neutrals in your target, or none at all. Not sure that this is a bug, but maybe its just a way to pad extra patches in an intelligent way. The near neutral patches may not be needed to get a decent grayscale. The old Monaco Profiler did a good job without needing the near neutrals. BTW, before you ask, I dont have a similar list for CMYK as those would be a lot more complicated. CMYK will follow a similar pattern of padding extra patches with near neutrals.
colorwiki.com/images/7/7f/I1 … utrals.png

I have also found that a slightly lower white point than 6500K gives me a better D50 match, ~ 6300 or so. If your only goal was to match your display to your light booth, then you could create printer profiles using the light booth illuminant. But for most people, the final goal is to make prints that will look correct in normal diffused daylight. (Thats pretty much what your customers are expecting even if they dont realize it.) To that end, we roll out printer profiles that are intended for D50 daylight, and we soft-proof on displays that try to come close to daylight, and we hard-proof in viewing booths that do their best to approximate daylight. All fluorescent lamps do have very narrow spikes in the green and blue spectrums, so that can throw things off in these very narrow ranges. Viewing booths are generally pretty good overall, but there are these caveats. Youre expected to replace the lamps after a certain number of hours, too.

So everything is geared toward getting prints that look good under daylight, and our other tools for proofing are trying to accomplish that the best they can. It’s certainly not perfect. But I have a feeling you are more discerning than your customers Laurent.:wink: