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Author Topic: Slight magenta cast on Canson Baryta Prestige - Canon Pro 4000  (Read 1062 times)

Nickilford

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Re: Slight magenta cast on Canson Baryta Prestige - Canon Pro 4000
« Reply #20 on: April 11, 2018, 01:10:23 PM »

The reason why I recommended this is because I and others have come across issues using ACPU for printing profiling targets with this printer driver. It comes from a recommendation that Canon technical support made to me when I was testing the Canon Pro-2000 printer, and I found that their advice produced a reliable path through "no colour management" which is necessary for successful profiling. Nothing prevents you of course from trying either, or from using i1Profiler for that matter, and observing any differences in outcomes. Could be interesting - just more ink, paper and time.

Thanks Mark, this is valuable info. Actually I just printed a target for Canson Aquarelle Rag via Canon's Print Studio Pro, the target for Prestige had already been printed yesterday through ACPU, sorry my mistake. I followed your instructions regarding the the patch count (2371) though, so i'm curious about the results. Will be reading the Prestige target shortly and will post outcome back here.
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Nickilford

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Re: Slight magenta cast on Canson Baryta Prestige - Canon Pro 4000
« Reply #21 on: April 15, 2018, 09:53:31 AM »

I reviewed this paper on this website, custom profiled it and noticed no such problem. I suspect of you remade the profile you would get better results. If you are using i1Profiler, try making your profile with the 2371 scrambled patch layout, test it and see what happens.

So, I re-profiled the Prestige with the 2371 scrambled patch and the results are better but not that much better. I had already printed the target via ACPU before the OP, so now i have printed through the Canon Print studio pro and am going to give it another go.

Btw, does the lighting i am reading the target under have any influence on profile quality?
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Mark D Segal

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Re: Slight magenta cast on Canson Baryta Prestige - Canon Pro 4000
« Reply #22 on: April 15, 2018, 10:32:11 AM »

So, I re-profiled the Prestige with the 2371 scrambled patch and the results are better but not that much better. I had already printed the target via ACPU before the OP, so now i have printed through the Canon Print studio pro and am going to give it another go.

Btw, does the lighting i am reading the target under have any influence on profile quality?

I haven't conducted any tests to know whether reading the targets under dim, bright or no light makes a difference, so I can't say. I normally read profiling targets under dim lighting, using an i1Pro 2 and the supplied baseboard and track. The i1Pro2 design looks as if it is protected from ambient light, but how much and how well I don't know.
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Mark D Segal (formerly MarkDS)
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andrewrodney

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Re: Slight magenta cast on Canson Baryta Prestige - Canon Pro 4000
« Reply #23 on: April 15, 2018, 11:21:50 AM »

Btw, does the lighting i am reading the target under have any influence on profile quality?
Not really unless you had a massive amount pointed at the unit etc. It’s pretty well blocked. The color under the paper could if not totally opaque. Maybe a 2nd blank sheet under the print target in such cases could be prudent.
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Andrew Rodney
Author “Color Management for Photographers"

Nickilford

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Re: Slight magenta cast on Canson Baryta Prestige - Canon Pro 4000
« Reply #24 on: April 15, 2018, 11:32:00 AM »

I haven't conducted any tests to know whether reading the targets under dim, bright or no light makes a difference, so I can't say. I normally read profiling targets under dim lighting, using an i1Pro 2 and the supplied baseboard and track. The i1Pro2 design looks as if it is protected from ambient light, but how much and how well I don't know.

This is how I usually read targets and have had good results so far.
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Nickilford

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Re: Slight magenta cast on Canson Baryta Prestige - Canon Pro 4000
« Reply #25 on: April 15, 2018, 11:33:30 AM »

It’s pretty well blocked.

My thoughts exactly! Just wanted to have more experienced people's thoughts on this. The papers I use are pretty heavy so i don't think opacity will be an issue.
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Mark D Segal

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Re: Slight magenta cast on Canson Baryta Prestige - Canon Pro 4000
« Reply #26 on: April 15, 2018, 11:34:36 AM »

Don't you use the backer-board that comes with the i1Pro2 kit? It's been designed specifically for neutral influence.
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Mark D Segal (formerly MarkDS)
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Nickilford

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Re: Slight magenta cast on Canson Baryta Prestige - Canon Pro 4000
« Reply #27 on: April 15, 2018, 11:36:26 AM »

Don't you use the backer-board that comes with the i1Pro2 kit? It's been designed specifically for neutral influence.

Yes I use all original accessories that come with the i1PP2.
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andrewrodney

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Re: Slight magenta cast on Canson Baryta Prestige - Canon Pro 4000
« Reply #28 on: April 15, 2018, 11:37:04 AM »

Don't you use the backer-board that comes with the i1Pro2 kit? It's been designed specifically for neutral influence.
Yes (when I use that product) but it's still a good idea to place another sheet of paper there and in the past, there was controversy about using a black backer instead of white.
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Andrew Rodney
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Nickilford

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Re: Slight magenta cast on Canson Baryta Prestige - Canon Pro 4000
« Reply #29 on: April 15, 2018, 11:50:34 AM »

Does the speed at which one reads each row have any influence on profile quality? I'm assuming that as long as you don't get an error all is good, but something keeps telling me that the slower you go the more time the sensor has to pick up info. What has been your experience?
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Mark D Segal

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Re: Slight magenta cast on Canson Baryta Prestige - Canon Pro 4000
« Reply #30 on: April 15, 2018, 12:15:24 PM »

Yes, speed matters. Up to a point, slower is better. As you pass over each patch, the instrument is reading a certain number of samples per second (I forget the exact specification), so passing over the patches more slowly increases the number of samples read per patch, which means that average for the patch will be more representative and presumably a more accurate representation of the printed colour.
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Mark D Segal (formerly MarkDS)
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Mark D Segal

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Re: Slight magenta cast on Canson Baryta Prestige - Canon Pro 4000
« Reply #31 on: April 15, 2018, 12:21:58 PM »

OK got it - in scanning mode 200 samples per second. So if you scan a whole row in 20 seconds, you have collected a total of 4000 samples; assuming an even pass, if there are 30 patches in the row, you would be picking up 133 samples per patch, which would be averaged for each patch.
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Mark D Segal (formerly MarkDS)
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Nickilford

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Re: Slight magenta cast on Canson Baryta Prestige - Canon Pro 4000
« Reply #32 on: April 15, 2018, 12:50:54 PM »

OK got it - in scanning mode 200 samples per second. So if you scan a whole row in 20 seconds, you have collected a total of 4000 samples; assuming an even pass, if there are 30 patches in the row, you would be picking up 133 samples per patch, which would be averaged for each patch.

Wow, this takes target reading to whole new level... I thought I was going slow at 5secs per row!
Thanks for the numbers, really puts things into perspective.

Just finished ready the target for Prestige, printed from Print Studio Pro, linear patches 2371. Be right back.
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Mark D Segal

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Re: Slight magenta cast on Canson Baryta Prestige - Canon Pro 4000
« Reply #33 on: April 15, 2018, 01:02:10 PM »

Did you let the target print dry for at least a few hours? There can be subtle colour shifts during the first few hours of dry-down. Some people give them overnight.
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Mark D Segal (formerly MarkDS)
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Nickilford

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Re: Slight magenta cast on Canson Baryta Prestige - Canon Pro 4000
« Reply #34 on: April 15, 2018, 01:11:37 PM »

Did you let the target print dry for at least a few hours? There can be subtle colour shifts during the first few hours of dry-down. Some people give them overnight.

Yes I usually give 24h, sometimes more.

Since i have had this printer i only use the ICC profile i created but in the MCT i have never used the Calibration target module. Will this help in any way even if i already use a custom profile?

P.S - just ran a test print and the result was worse than the profile i scanned yesterday. I may be being a bit too nitpicky here, taking a closer look I might be mistaking a higher saturation in certain areas than an actually color shift....
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Doug Gray

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Re: Slight magenta cast on Canson Baryta Prestige - Canon Pro 4000
« Reply #35 on: April 15, 2018, 02:18:46 PM »

You need a defined process to cross check profiles. This means a test of independent colors, not used in the creation of the profile, printed using normal, Photoshop manages color and selecting the intent and profile.

Then, measure the printed colors.

Easiest way by far is to grab a tiff image of a ColorChecker from BabelColor. Print it selecting Abs. Col. then measure the 24 patches using the "Measure" tab and select a 4x6 grid layout to match the Colorchecker. Use spot measure for the I1Pro or I1Pro2.

Now compare the Lab values by clicking on each patch. Compare to those examining the image in Photoshop. You should see an average dE of 1 or less except for the white patch which is often outside the printable gamut unless the paper white is above L*=96.

Pay special attention to the neutral patches on the bottom of the CC.

You can also save the measurements by selecting the save button. Select a CGATs format for simple reading with a text editor or Excel. Makes it easier to collate the data.
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andrewrodney

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Re: Slight magenta cast on Canson Baryta Prestige - Canon Pro 4000
« Reply #36 on: April 15, 2018, 02:54:08 PM »

Does the speed at which one reads each row have any influence on profile quality?
To a minor degree yes in that it scans 100 samples a second and averages them but if you go too fast, you'll get an error and that's a lot of sampling. Perhaps with canvas or some textured paper it might be somewhat prudent to move a bit more slowly but even 1 'good' measurement would likely be enough. At least in the old days, many Spectrophotometer's only needed one.
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Andrew Rodney
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Mark D Segal

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Re: Slight magenta cast on Canson Baryta Prestige - Canon Pro 4000
« Reply #37 on: April 15, 2018, 03:06:08 PM »

No big deal, but according to the specs (i1Pro2) it's 200 per second, which is better of course.
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Mark D Segal (formerly MarkDS)
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andrewrodney

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Re: Slight magenta cast on Canson Baryta Prestige - Canon Pro 4000
« Reply #38 on: April 15, 2018, 03:31:10 PM »

No big deal, but according to the specs (i1Pro2) it's 200 per second, which is better of course.
Yes, than i1Pro which is 100; which is the OP using?
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Andrew Rodney
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Doug Gray

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Re: Slight magenta cast on Canson Baryta Prestige - Canon Pro 4000
« Reply #39 on: April 15, 2018, 03:33:42 PM »

One difference the I1P and I1Pro 2 have over the older I1Pro is that chart scanning is done with quadrature position sensing on the underside of the Spectro. The earlier one looked for contrast differences between adjacent patches because it didn't have the quadrature position info. The contrast info that matters is the white/black bars at each row end. This establishes the patch locations using the quadrature info. If it's anything like the iSis, it heavily weights middle samples that are 2 mm from the actual patch edges. This is actually testable and I've done that for the iSis. Might be interesting to do for the I1Pro 2.
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