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Author Topic: Colorchecker Passport DNG profiler running out of memory on large files  (Read 1476 times)
feppe
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« on: October 28, 2012, 06:14:12 AM »
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I have drum scanned photos that I'd like to profile, but I keep running out of memory with X-Rite's DNG profiling software that came with ColorChecker Passport.

The files are massive. X-Rite's software only takes DNGs, so the original TIFF files have to be converted to DNG with LR. I cropped the photos to only include the target, but that didn't help with memory. LR doesn't actually crop anything when exporting to DNG, but merely puts metadata field telling where the crop is.

So, how do I get around this? Is there a way to force-crop the DNGs, or a method to manually create a profile using the 24-color target?
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Rand47
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« Reply #1 on: October 28, 2012, 08:31:48 AM »
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Crop / resize the tiff in PS CS6 before bringing into LR?
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digitaldog
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« Reply #2 on: October 28, 2012, 09:36:25 AM »
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I have drum scanned photos that I'd like to profile, but I keep running out of memory with X-Rite's DNG profiling software that came with ColorChecker Passport.

That isn't the product you want to be using for profiles for a drum scanner for one.

Do you have an IT8 or some good reflective and/or transmissive target?
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Andrew Rodney
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Rand47
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« Reply #3 on: October 28, 2012, 11:58:35 AM »
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That isn't the product you want to be using for profiles for a drum scanner for one.

Do you have an IT8 or some good reflective and/or transmissive target?

What I had assumed from the OP's post is that he'd shot the Colorchecker passport target in one of his scanned trannys.  Would not a DNG profile made from one of this file be useful to apply to the others of this shoot?
Not a challenge to your comment, a request for information and understanding.
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digitaldog
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« Reply #4 on: October 28, 2012, 12:11:02 PM »
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Would not a DNG profile made from one of this file be useful to apply to the others of this shoot?

Well for one, the DNG profile is used within an Adobe raw converter to deal with raw data which isn't what the scanner is producing. It is creating a rendered RGB TIFF and that process is what needs to be profiled. You'd need a true ICC profile to do this, you'd feed the software the RGB TIFF (can be a few megs too), then ideally you'd use that profile within the drum scanning software.

DNG profiles are for actual raw camera files that are not rendered, and are used within LR or ACR.

Saving a rendered RGB TIFF as a DNG doesn't make that data raw (or scene referred data). The TIFF is just within the DNG container. Just lke the same data from the scanner saved as a PSD or TIFF is the same data, just the file format is different.
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Andrew Rodney
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Rand47
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« Reply #5 on: October 28, 2012, 12:22:07 PM »
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Well for one, the DNG profile is used within an Adobe raw converter to deal with raw data which isn't what the scanner is producing. It is creating a rendered RGB TIFF and that process is what needs to be profiled. You'd need a true ICC profile to do this, you'd feed the software the RGB TIFF (can be a few megs too), then ideally you'd use that profile within the drum scanning software.

DNG profiles are for actual raw camera files that are not rendered, and are used within LR or ACR.

Saving a rendered RGB TIFF as a DNG doesn't make that data raw (or scene referred data). The TIFF is just within the DNG container. Just lke the same data from the scanner saved as a PSD or TIFF is the same data, just the file format is different.

Thanks for the lesson!  OK, so I'm going to show my ignorance a little more here.  Since LR is still parametric even w/ tiff files, and once the Colorchecker profile is created it is much like a "camera profile" that can be applied, it seems like what you have told me is sort of moot?  Wouldn't LR apply the profile to a tiff file?  Or, is it that it "would" but that it would be sub-optimal way of going about this? 

I do understand what you've said about profiling at the scanning stage as logical and preferred.  If that's even the right terminology.

Thanks for the lessons, very helpful in my learning outside of my own little knowledge box.  Apologies to the OP if my diversion is diluting the thread - but it seems to me my questions go directly toward your original issue.
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digitaldog
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« Reply #6 on: October 28, 2012, 12:28:01 PM »
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Even though rendered images are passed through the same engine as raw, the results are not the same. And the place to be setting the overall global tone and color corrections are at the scan stage (faster and potentially better data).

The idea is to profile the scanner! If you scan something then pass it onto a totally different process, well you just bypassed the importance of profiling the scanner itself, then you pass a lot of processing onto a product that could be used but wasn't designed for the task.
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Andrew Rodney
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Rand47
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« Reply #7 on: October 28, 2012, 12:33:36 PM »
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Thanks... your helpfulness is appreciated.

Rand
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Czornyj
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« Reply #8 on: October 28, 2012, 12:38:15 PM »
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I'd try using ArgyllCMS to create a traditional ICC profile, that you can assign in PS.

BTW - I always regretted there's no way to get RAW files from scanner, use CC24/SG and DNG profile editor to create DNG profiles, and edit scans using LR/ACR. It would be perfect for negatives, that can't be profiled with IT8/HTC tagrets.
« Last Edit: October 28, 2012, 12:40:04 PM by Czornyj » Logged

Marcin Kałuża
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« Reply #9 on: October 28, 2012, 12:59:23 PM »
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Neg's are severe bitch to profile (if it's even possible). The orange mask and it's effect on the image which changes based on exposure and processing make it really difficult to profile. So the creation of just a target was very problematic unlike making a transparency or reflective target.

As for raw out of a scanner, do you really want a single channel Grayscale (in need of demosaicing) instead of true tricolor capture?

Some of the drum scanners I ran (those driven by LinoColor) did a pretty good job with color negs. The Imacon's did a very good job if you knew a few tricks and let it build a custom setting for that group of negs. I always had to create a new small crop inside a group of negs, move the crop around the image and hit Auto (if memory serves me) and when the image looked pretty good, save that and use that setting for the other negs in the group. Pop in negs shot and processed differently and the saved setting previously made usually didn't work. The old Leaf scanners were similar in this respect too.
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Andrew Rodney
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« Reply #10 on: October 28, 2012, 03:26:14 PM »
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As for raw out of a scanner, do you really want a single channel Grayscale (in need of demosaicing) instead of true tricolor capture?

raw != a single channel... think Foveon for example (you need complex color transforms, but you do not need a demosaicking)
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deejjjaaaa
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« Reply #11 on: October 28, 2012, 03:31:26 PM »
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DNG profiles are for actual raw camera files that are not rendered
if my scanner output is RGB tiff without any curves applied (linear gamma) and RGB was not colortransformed into any regular colorspace it is as not rendered and is as "scene referred" as in case of DNG profiles, is it not ?
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digitaldog
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« Reply #12 on: October 28, 2012, 04:13:12 PM »
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if my scanner output is RGB tiff without any curves applied (linear gamma) and RGB was not colortransformed into any regular colorspace it is as not rendered and is as "scene referred" as in case of DNG profiles, is it not ?

I don't know how the application or lack of the application of curves make this more or less 'raw'. I've been scanning images for 20 years, dating back to the Leaf 45 and I've used a lot of scanners, PMT Drum and otherwise and I've always wanted the most faithful visual match to the original I'm scanning. I can always alter that too. But a close match is the starting point at the very least. I've profiled scanners after trying to find the settings that produce the best data and visual match. So I'm foreign to this idea of a 'raw' scan unless in such a case, the setting driving the scanner is providing this AND more importantly best data and match.

I do recall Bruce Fraser and I trading notes on our use of Imacon scanners years back and finding that a Gamma 3.0 setting provided the best data for profiling. That's simply one example, and illustrates at least with this scanner, linear curves were not a target we'd be looking forward to using. Maybe on your particular scanner hardware it is.

And no, none of the above is scene referred. The thing I have to digitize and reproduce is the thing I put on my scanner and a reason the target and how that target is scanned and what software builds an ICC profile is kind of important.
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Andrew Rodney
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feppe
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« Reply #13 on: October 28, 2012, 06:13:07 PM »
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Yes, I included a Passport target as shot in the scanned trannies. These are Provia scans done by a service, so I don't have access to the scanner, and I doubt the guys are willing to calibrate every shot. Although maybe they should, given the price they charge...

I could use the grayscale patches to get the basics right, but I would prefer to do a more thorough profile for each shot with the 24-patch target. So, would ArgyllCMS be able to create a useful profile (never used it)?
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