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Author Topic: Epson V700 Blown Highlights on Reflective Scans with Silverfast AI 8 Studio  (Read 8843 times)
Stephen G
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« Reply #20 on: November 05, 2012, 12:35:00 PM »
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One question though: does the profile replace the scanner profile in silverfast, or does it get applied to the image in photoshop after scanning?


Either way works. Although, if you go the route of assigning it yourself in photoshop you are cutting your workflow in Silverfast short at the point when you exported your target scan. May or may not be a disadvantage to you.

I didn't get a chance to play with CoCa again today, but I did collect a new watercolour pencil drawing to reproduce that I'll run with a CoCa profile. I'll post here about how it goes.
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Mark D Segal
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« Reply #21 on: November 05, 2012, 12:45:08 PM »
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Either way works. Although, if you go the route of assigning it yourself in photoshop you are cutting your workflow in Silverfast short at the point when you exported your target scan. May or may not be a disadvantage to you.


Stephen yes, you're right - either way works, but just to amplify on what those ways are: two options here: (1) do a "raw" scan in SilverFast, then open the image in Photoshop and "Assign" your scanner profile. OR (2) In SilverFast Preferences> CMS select the scanner profile in the Input/scanner pane and make sure Colorsync is also active. As you are purposing the images to a print, I recommend scanning in ProPhoto colour space and using ProPhoto in Photoshop as well. And that means making sure to scan and work in 48-bit RGB (i.e. 16-bit per channel). Keep your master file in 16-bit, and if you need for example sRGB JPEGs for quick transmission, create copies in Photoshop that you shrink to 8-bit for this purpose.
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Mark D Segal (formerly MarkDS)
Author: "Scanning Workflows with SilverFast 8....." http://www.luminous-landscape.com/reviews/film/scanning_workflows_with_silverfast_8.shtml
Stephen G
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« Reply #22 on: November 06, 2012, 08:52:46 AM »
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I got a chance to run the job I collected yesterday through CoCa profiles. They are very useable for my purposes. Different to the PM5 generated profiles, but just as good, if not better in some respects. I have slightly fewer and simpler corrections to do to get a match than I do with the PM5 profiles.

The LAB Clut algorithm is the one that I use, whitepoint pushed to 1.2, quality Ultra High (might as well, doesn't take THAT long). Needs a slight exposure correction after assigning but at least the highlight data is safely in the masterfile.

The attached picture shows the difference between the algorithms. No white point tweaks or extensions on these. The crops are, from left to right, Gamma Matrix, LAB Clut, Shaper Matrix, XYZ Clut and PM5.

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Mark D Segal
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« Reply #23 on: November 06, 2012, 09:13:16 AM »
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Stephen,

They all look pretty good to me and hard to see much difference between them. What I would find most useful, if you are positioned to do it, is to see how those results compare with using a profile for your scanner from SilverFast or another external provider, so we can compare the difference it makes relative to the careful procedures and high-end materials you are deploying for this purpose.
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Mark D Segal (formerly MarkDS)
Author: "Scanning Workflows with SilverFast 8....." http://www.luminous-landscape.com/reviews/film/scanning_workflows_with_silverfast_8.shtml
dmerger
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« Reply #24 on: November 06, 2012, 11:33:31 AM »
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I don't know if CoCa qualifies as "high-end".  CoCa is free. So, maybe the results are "high-end", but certainly not the price.  Wink
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Dean Erger
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« Reply #25 on: November 06, 2012, 11:43:24 AM »
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Ya but the target he's using costs between USD 250~300  :-)
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Mark D Segal (formerly MarkDS)
Author: "Scanning Workflows with SilverFast 8....." http://www.luminous-landscape.com/reviews/film/scanning_workflows_with_silverfast_8.shtml
Stephen G
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« Reply #26 on: November 06, 2012, 01:17:02 PM »
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Colour is pretty similar across those images, but if you look into the yellow band you'll see that the second one, LAB clut algorithm, is the smoothest. The others are all a bit bandy, like the brightest bits are on the ragged edge of clipping.

I'll post similar tomorrow using the epson canned profile, an HCT profile and whatever other ones I can dig up. I'll try get CoCa to build profiles from my CC24 and qpcard203 if I have time too.

Hmm, I seem to have collected quite a few targets.
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TylerB
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« Reply #27 on: November 06, 2012, 01:18:40 PM »
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one other issue of note, whether it applies to this problem or not, is that some scanner profiles clip whites when converting to working space depending on intent. Monaco scanner profiles, for example, do so using perceptual, therefore requiring colormetric. THere is a lot of great info about scanning and color management here, if you dip deep-

http://www.hutchcolor.com/index.html

Tyler
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Stephen G
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« Reply #28 on: November 06, 2012, 01:26:00 PM »
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one other issue of note, whether it applies to this problem or not, is that some scanner profiles clip whites when converting to working space depending on intent. Monaco scanner profiles, for example, do so using perceptual, therefore requiring colormetric.

Dang. Haven't played with rendering intent when converting from scanner profile to working space. Just assumed it was fixed at relative like when you convert between working spaces.
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Stephen G
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« Reply #29 on: November 07, 2012, 05:57:21 AM »
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I'll post similar tomorrow using the epson canned profile, an HCT profile and whatever other ones I can dig up. I'll try get CoCa to build profiles from my CC24 and qpcard203 if I have time too.

OK so it won't be today. I've been playing with the demo of Silverfast a bit, its V700 profile seems pretty good. I'll put something together and post again soon.

Stephen
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Mark D Segal
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« Reply #30 on: November 07, 2012, 07:03:55 AM »
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Looking foreward to what you come up with Stephen.
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Mark D Segal (formerly MarkDS)
Author: "Scanning Workflows with SilverFast 8....." http://www.luminous-landscape.com/reviews/film/scanning_workflows_with_silverfast_8.shtml
chaddro
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« Reply #31 on: November 07, 2012, 07:40:55 AM »
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Hi Mark, yes, they are! I was able to get mine effectively unused off "e" bay ... for $120. If you're patient and very persistent you can often get lucky.

BTW, your Angkor gallery are really awesome! Thank you for sharing. 

Stephen, I like the results your getting with Coca. It will be interesting to see how they compare to the canned profiles. Although I've finished with the stamp project for now, I'm going to give this a try.

I'm getting more and more scanning projects so all this information is quite useful.




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Mark D Segal
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« Reply #32 on: November 07, 2012, 07:57:20 AM »
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Thanks Chadd, glad you enjoyed them.
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Mark D Segal (formerly MarkDS)
Author: "Scanning Workflows with SilverFast 8....." http://www.luminous-landscape.com/reviews/film/scanning_workflows_with_silverfast_8.shtml
Stephen G
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« Reply #33 on: November 12, 2012, 05:37:41 AM »
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Posting a bit later than I thought I would, apologies, but last week got a bit busy. I've put together a set of images for comparison. All are saved in AdobeRGB so it's probably best to view them in PS unless you trust your browser. All files were passed through LR for the downsample from original to the res you see here.

final colour.jpg - from my masterfile. This file prints a close match to the original drawing.
SilverFast No adjustments.jpg - straight out of Silverfast
PM5 DCSG No Extension.jpg - Vuescan Raw; assigned PM5 generated profile; DCSG target; no highlight extension
CoCa DCSG Lab Clut No Extension.jpg - Vuescan Raw; CoCa generated profile; DCSG target; Lab Clut algorithm; no highlight extension

Three more crops and discussion in next post.
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Stephen G
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« Reply #34 on: November 12, 2012, 06:01:45 AM »
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PM5 HCT No Extension.jpg - as for DCSG above
PM5 HCT Extended.jpg - as above, but highlights extended significantly
CoCa QP203 Gammamatrix WP 1.2.jpg - CoCa generated profile from QP203; Gamma+Matrix algorithm; White Point 1.2

Haven't thought this through into an essay so here are some points that have struck me:
- Silverfast's generic V700 profile yields very good colour. It does compress the contrast, however, which would need to be fixed to get a match. Mainly it's the highlights that get squished - instead of being bright and clear they are a little murky.
- There really isn't much between the PM5 and the CoCa profiles. I can get a good match fairly easily with either. PM5 seems to retain a little more detail in the highlights, but loses a nitpicking touch of absolute accuracy. I'm running with the CoCa profiles for now and will continue to do so unless they start presenting issues.
- note how massively the un-extended HCT profile clips. not an appropriate target for this work. it's great for photographic prints, of course.
- the extended HCT profile enters the realm of useability, but needs lots of contrast and colour work for a match. (this is actually how I started this kind of work last year, before trying the DCSG)
- for interest I included a CoCa profile generated from my QP203. Generic reference file. The Lab Clut algorithm gave awful results, but the Gamma+Matrix with a white point tweak seems to be OK. It's rather punchy and oversaturated, but it's not a horrible profile. Not bad for a $50 target and not-ideal reference data.

That's it for now.

All of these crops are reproduced with the kind permission of the artist. If you are interested in seeing a bit more of the work, please visit her site lindsaysdesigns.com 
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Stephen G
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« Reply #35 on: November 12, 2012, 06:33:16 AM »
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A sleeper! Attached is a scan from Epson Scan - the utility that comes with the scanner. I've never delved into it until now but I decided 10 minutes ago to try and get it to produce as flat a scan as it possibly could. I zeroed all the automatics, levels and curves that I could find, told it to use its generic scanner source profile and then convert to AdobeRGB.

It's incredibly similar to the Silverfast results! The silverfast scan has better colour, I think, but there's not much to it.
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Mark D Segal
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« Reply #36 on: November 12, 2012, 09:19:18 AM »
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Hello Stephen,

First, we all owe you much thanks for taking the time and trouble to run these tests and prepare the results. I know from my own experience designing, performing, evaluating and writing-up tests, it takes time and concentration.

I have opened all your provided files in PSCS5, looked them over on my properly calibrated and profiled NEC PA271W display, and have the following observations, assuming that the "final" is the one that looks closest to the original media that you are scanning; I see them falling into three categories

(1) PM5 DCSG No Extension and PM5 HCT Extended look to me as the ones that provide the closest "out of the box" outcomes to the final.
(2) The two CoCa and the PM5 HCT No Extension look to me the riskiest in terms of losing detail to either saturation or highlight issues.
(3) The SilverFast and EpsonScan results are indeed very close to each other, but both showing less contrast and brightness than the "final". This also makes them safer than category (2), because it is very easy to add-in a bit of punch and brightness, totally under the operator's control, to get to "final" without risking loss of wanted image detail.

Hence based on your results from this sample, which is a useful one, I would be comfortable with the profiles in categories (1) and (3), using whichever is the most convenient and least-cost to obtain.
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Mark D Segal (formerly MarkDS)
Author: "Scanning Workflows with SilverFast 8....." http://www.luminous-landscape.com/reviews/film/scanning_workflows_with_silverfast_8.shtml
dmerger
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« Reply #37 on: November 12, 2012, 12:49:14 PM »
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Stephen, your test is very interesting.  Thanks for posting your results.

The profile that provides the best match with the original art obviously is the best profile for your purposes.  The potential problem I see, however, especially in trying to extend your test results to film scans with lots of detail and subtle color and tone differences, is that most of your samples have very significant highlight clipping (except for the PM5 HCT Extended which just mainly clips the white area and the Epson and Silverfast profiles which have minor clipping).  Just looking at your reduced sized jpegs, it appears that many of your profiles result in some loss of detail in the clipped areas.  To me, from a detail perspective, it looks like the PM5 HCT Extended profile may be the best, followed closely by the Epson and then the Silverfast.  It would be interesting to see if you could open the PM5 HCT Extended or Epson version in LR and make a few quick adjustments that would give you the color match similar to your final version, but with a little more detail.

The problem I find in determining if there is true highlight clipping in scans, especially in the individual color channels, is that no desktop scanning software that I know of permits output of true RAW data from the scanner CCD.  So, itís difficult to determine whether you have RAW clipping or the clipping is introduced at the profiling stage.  Furthermore, clipping could be introduced, extended or hidden upon conversion from your custom profile to another color space such as aRGB.  Depending on your scanner and scanning software, the best you may be able to do is check for clipping at multiple stages to see what you can learn.  For example, if you can output 16 bit linear data, you can check that data.  You can check for clipping upon applying your custom profile and again after you convert to aRGB or another color space. 

Of course not all clipping is necessarily harmful.  Also, if you canít physically alter the amount of light reaching your scannerís CCD, then you may have no way to prevent RAW clipping. And the most important caveat Ė if youíre getting the results you want despite some clipping, then ignore everything Iíve written about clipping!  Embarrassed
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Dean Erger
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« Reply #38 on: November 12, 2012, 01:30:29 PM »
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Dean, I'm wondering firstly, whether we're downloading and looking at the same stuff. In my post above I was examining the JPEGs that Stephen attached as illustrated in his posts. Did I miss anything Stephen?

Secondly, assuming we looking at the same stuff, I don't get the extent of highlight clipping you are referring to except in the category (2) scans and to a minor extent only a small bit of red channel clipping in the category (1) scans. Also recall these are compressed JPEGs, so some allowance needs to be made for the possibility that data loss may be adversely affecting our appreciation of this issue. The Silverfast and Epson scans are not clipped at all in my version of PSCS5. I am opening the files using the "Preserve Embedded Profile" option. Are you doing the same? I find the Epson and SilverFast results to be pretty much interchangeable and unclipped, which would help explain why they are of somewhat lower contrast and brightness - and therefore "safer" starting points.

Thirdly, my understanding is that these are reflective scans, which should have been made from profiles generated with reflective targets, and if that's the case, until it's tested it's not clear what they imply for any particular profile generated for transparencies from a transparency film target.

In both SilverFast and Vuescan, we can output a linear gamma scan with no further luminance and colour adjustments, which is the closest we'll get to producing what the CCD registers. So we can assess clipping on that basis as a starting point. A question for Stephen would be the gamma factor used in his profiling and scans, and whether it is the same across all samples.
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Mark D Segal (formerly MarkDS)
Author: "Scanning Workflows with SilverFast 8....." http://www.luminous-landscape.com/reviews/film/scanning_workflows_with_silverfast_8.shtml
dmerger
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« Reply #39 on: November 12, 2012, 02:41:07 PM »
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Mark, I downloaded the jpegs, opened them from Bridge in PS-CS4 in layers with the embedded aRGB profiles, then added a levels layer on top to check for clipping.  My method shows significant highlight clipping, particularly in the red channel, in 5 out of the 8 samples. The other three samples also show clipping as I described above. I have no idea why you get different results.

Yes, the jpeg compression could account for some or all of the clipping, which is why I mentioned that I just looked at Stephenís reduced sized jpegs.  Conversion from Stephenís profiles to aRGB may have also contributed to the clipping. These are issues that Stephen will have to look into as I described in my prior post.

Itís difficult for me to make a fair comparison of the Epson and Silverfast profiles due to their different sizes.  They look very similar, but I think I detect a small difference.  I could be wrong.

Yes, Stephenís scans are reflective scans, and Iím not sure how much can be extrapolated to film scans.  My point was about clipping and whether some profiling methods introduce clipping.  If so, it would be something to look for when using CoCa, for example, for film scans.

I use 16 bit linear output as one way to check for clipping (highlight and shadow).  Itís not as good as RAW data, but, as you mentioned, itís the closest to RAW as we can get. In other words, there is a possibility that however you examine a 16 bit linear tiff, the fact that it shows or doesnít show clipping is no guarantee that the RAW data does or does not have clipping.  Since I have no way to look at the RAW data, Iíve tried to convince myself that the 16 bit linear data is close enough.   Roll Eyes
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Dean Erger
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