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Author Topic: Epson V700 Blown Highlights on Reflective Scans with Silverfast AI 8 Studio  (Read 8610 times)
chaddro
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« on: November 02, 2012, 05:36:24 PM »
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Hi All!

I am scanning a number of stamps from the 20's and 30's for a client project. The paper is quite matte and there is no shine to it. As a backer for the stamps (they've been removed from the envelopes) I'm using a white matte acid free cotton paper so they look mounted (well, sort-of!).

One of the problems I'm having is at the leading edge (top of the stamp) I'm getting blown highlights. And histogram is piled up against the right.

I have tried quite a few options from within Silverfast AI 8 to fix this, turned off most/all of the auto adjustments, but still can't seem to pull the exposure down.

Yes, there is an "Exposure" slider, but all it does is pull the data to the left, it doesn't actually "stop down" the scanner so I don't get an over exposed scan.

I'm hoping someone can point me in the right direction. Really banging my head against the wall on this one.

Thanks!
-chadd

Mac OSX 10.6.8 + Epson V700 + Silverfast Studio Ai 8.0.1.r17
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Mark D Segal
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« Reply #1 on: November 02, 2012, 07:04:06 PM »
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Hi Chadd,

I just tried replicating your problem, as I have the V750 scanner (same profiles and scanning specs) with SF8 Ai Studio. The default scan produced an overexposed prescan, highlights fringing on clipping, with little to distinguish the three different shades of white (see illustrations) and histogram values bunched to the right, I suppose like you got. I opened the histogram tool, Expert dialog, clicked on Color Cast Removal and made sure the slider was at 100. This solved the problem. Clipping disappeared from the output histogram, (but the input histogram did not update). No matter, the Densitometer shows that there are no clipped values and the three shades of white are clearly distinguishable in the adjusted settings. Give it a try. You can also go into "Preferences> Auto" and shift the "Auto-adjust Darker" slider rightward and see to what extent that helps.

Scanning applications don't have highlight recovery like we have in Lightroom or Camera Raw, where rather than just turning clipped values from white to gray as you reduce exposure, the Adobe applications simulate RGB values having colours. If you can succeed in getting the scan values below level 255 in all three channels or even in two of three, make the scan, open it in Lightroom and try additional highlight taming there.
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Mark D Segal (formerly MarkDS)
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chaddro
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« Reply #2 on: November 02, 2012, 07:45:36 PM »
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Hi Mark!

Thank you for your valuable input. The Color Cast Removal at 100 checked did help. I also gave the Auto Adjust Darker slider a value of 5. I'm now getting a very good pre-scan.

The Auto Adjust Darker/Lighter sliders were both set to 15. Perhaps that was also complicating things.

A couple more questions for you if that's okay...

1) Is it better to adjust the image after scan, or okay to tweak the Output Histogram in Silverfast? My goal would be to bring out the texture of the paper a bit more.

2) From your experience do you think that Lightroom 4's sharpening is superior to Photoshop CS 5's sharpening? I have both.

I've been asked to make 30" canvas prints of these 1" high stamps. The stamps are illustrative line art so I feel it's quite doable.
I'd be also interested on your thoughts of sharpening something like this.

For myself, I've been converting to LAB and sharpening on the L channel with very acceptable results.

Thank you again for your suggestions!

-chadd

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Mark D Segal
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« Reply #3 on: November 02, 2012, 08:21:28 PM »
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Hi again Chadd,

Glad that all worked.

The workflow questions you ask are perennial, there isn't one unambiguous answer and as usual - "it depends". I go into a lot of this in my book on SilverFast, so if you wish to explore this topic in more depth I'll be unbashful enough to recommend my book to you. Click on the link under my signature. But let me try to respond here and now to the extent reasonable: My general approach is to get the scan as close to a finished product as the scanning software allows. That way, you bring it into a post-scan image editor in pretty decent shape, and that gives you more degrees of freedom for further adjustments while preserving the basic quality and integrity of the image. So if you find that making luminosity adjustments in SilverFast improves the appearance of texture of the paper in the SilverFast Prescan, by all means do it. It's just important to bear in mind that a scan bakes in whatever you scanned. Also, because you intend to make very big enlargements of these scans, use the scanner's highest optical resolution and largest scan dimensions you can before the Res slider in the image dimensions panel departs from the green zone. Use this panel in "Expert" dialog mode. Also make sure to scan in 48-bit RGB mode.

As for sharpening, I'm a big fan of two sharpening tools that I think are really state of the art - Lightroom capture sharpening in the Detail panel, but if working in Photoshop, the Pixelgenius Plug-in Photokit Sharpener 2. If you intend to sharpen in either of these applications, do not sharpen in SilverFast. Also, either of these tools completely obviates the nuisance of Lab conversions and they work superbly well. While on this subject and going back to your objective of making big enlargements that well show the paper texture, you may find that Lightroom's Clarity tool, as well as its Contrast tool would make a useful contribution. You can play non-destructively with various combinations of Clarity, Contrast and Sharpening to get the effect you like. Also within Photoshop, the Photokit Sharpener 2 package has Creative Sharpeners that will help a lot. The key, however, is to make sure the pixels get scanned-in at high resolution with no clipping.
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Mark D Segal (formerly MarkDS)
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dmerger
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« Reply #4 on: November 02, 2012, 11:21:00 PM »
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Chadd, for comparison, here's a copy of Mark's first, unadjusted stamp that I edited very quickly in LR to bring out the paper texture.
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Dean Erger
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« Reply #5 on: November 03, 2012, 07:12:21 AM »
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Just a thought for the OP: what profile are you using for the scanner? If the white point of the target used to generate the scanner profile is not as bright as the white point of the stamp then the profile, once assigned, will clip the whites of the stamp.

Solution? use a target with a very bright white point (like a Colorchecker SG) to generate the profile. Targets printed on regular photographic paper (i.e. fuji crystal archive) don't have very bright white points.

I also have a V700 and had this problem for a while with scans of watercolour paintings. Some watercolour paper is seriously bright and I was losing the paper colour and the faint colour washes. My first target was an HCT, which has a low white point.
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Mark D Segal
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« Reply #6 on: November 03, 2012, 08:30:13 AM »
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Chadd, for comparison, here's a copy of Mark's first, unadjusted stamp that I edited very quickly in LR to bring out the paper texture.

Good job Dean, and shows what lies "under the hood" from that scanner and software once it is brought out properly.
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Mark D Segal (formerly MarkDS)
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« Reply #7 on: November 03, 2012, 09:14:44 AM »
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Just a thought for the OP: what profile are you using for the scanner? If the white point of the target used to generate the scanner profile is not as bright as the white point of the stamp then the profile, once assigned, will clip the whites of the stamp.

Solution? use a target with a very bright white point (like a Colorchecker SG) to generate the profile. Targets printed on regular photographic paper (i.e. fuji crystal archive) don't have very bright white points.

I also have a V700 and had this problem for a while with scans of watercolour paintings. Some watercolour paper is seriously bright and I was losing the paper colour and the faint colour washes. My first target was an HCT, which has a low white point.

The first thing I verified before posting a response to the OP was the colour management settings in Preferences>CMS. I determined that the software was pulling the correct profile for reflective scans using this scanner class. That of course is a canned profile provided by LaserSoft Imaging (LSI) based on their profile-making using their unit of that scanner model. The quality of the canned profile for the OPs' particular scanner then depends on any performance differences between his scanner and the scanner LSI used for generating the profile. As Epson manufactures these professional units to a high standard of uniformity (judged by lack of evidence to the contrary), the normal expectation is that the canned profile should do a pretty good job on most of the users' units.

However, in case it doesn't, as you may know, SilverFast 8 Ai Studio does have an Auto-IT8 profiling capability, and LSI makes available their reflective IT8 target for users to generate their own profiles. My copy of this target was printed on Kodak Professional Endura. To test the difference between the canned profile and a custom profile for my scanner, I created a custom profile with it. It turned out that in terms of white point and white balance, the custom profile and the canned profile are very similar - not the same but close. The main difference was a correction of 2 levels in the a* and b* channels shifting the colour balance from very slightly bluish to a more neutral rendering. In both cases the measured white point picked up from the LSI IT8 target is L90. "Maximum white" would be L100, and middle gray L50. The fact that a profiling target itself does not contain a patch having L* closer to 100 does not necessarily mean that any brightness values exceeding the maximum L* of the profiling patch would be clipped. That very limited universe of patches on a profiling target merely provides the sampled base data or anchors for algorithms in the computer's CMM that use this information to calculate millions of tones and colours that will be all over the place - above, below, and beside the values of individual patches in a profiling target. The better success you obtained making your own profile is most likely due to the possibility that your custom profile better replicated the behaviour of your scanner than the profile you were using previously. 

All that said, not impossible that in principle profiling and CM performance can have something to do with clipping image data, but in this case, especially in light of what Dean and I did above, I doubt very much this is the issue.
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Mark D Segal (formerly MarkDS)
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Stephen G
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« Reply #8 on: November 03, 2012, 10:56:31 AM »
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The better success you obtained making your own profile is most likely due to the possibility that your custom profile better replicated the behaviour of your scanner than the profile you were using previously. 

All that said, not impossible that in principle profiling and CM performance can have something to do with clipping image data, but in this case, especially in light of what Dean and I did above, I doubt very much this is the issue.

Your last paragraph made me read the first two posts again, a little more carefully this time. I guess I just reacted to the concept of his problem and threw out a suggestion based on my experience.

I must re-iterate, however, that I was comparing two custom profiles: one made with the HCT, one with the DCSG. HCT profile gave me clipped highlights, DCSG profile contained them.

I could extend the HCT profile by fiddling the white point of the target scan, but this gave me extra work to do with exposure and contrast correction. The DCSG target with its brighter white point was just a neater solution.
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chaddro
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« Reply #9 on: November 03, 2012, 12:01:41 PM »
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Thank you both for you additional input. I did try messing around with the CMS settings to see what they would get me, but the default canned reflective profile seemed to do better than anything else I tried. Turning off all the CMS setting really bunched the histogram up to the right side.

I do have a Digital ColorChecker SG, but I hadn't thought to try to roll a custom profile for the v700. I had looked at the it-8 features of Silverfast long ago, but really don't know which target to get or if I really needed one... This was the first time I had this kind of trouble with me scanner.

Dean, does your e-book cover scanner profiling?

I ended up using Photoshop for sharpening using LAB and the L channel method. I'm sure Lightroom can produce superior results, but my first attempts weren't going well and I absolutely had to finish printing last night (finished at 3 am!). I can spray coat today and deliver tomorrow, so I'm really grateful for the timely help!

Stephen, I'd be interested in your workflow for creating profiles for the v700 with your DCSG.

Again, thank you both for your help.

-chadd
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Mark D Segal
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« Reply #10 on: November 03, 2012, 12:06:24 PM »
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I don't know that Dean has an e-book, but my e-book does. However, the profiling discussion focuses on using SilverFast 8 and its targets.
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Mark D Segal (formerly MarkDS)
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« Reply #11 on: November 03, 2012, 12:06:58 PM »
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I must re-iterate, however, that I was comparing two custom profiles: one made with the HCT, one with the DCSG. HCT profile gave me clipped highlights, DCSG profile contained them.


OK, I can see where you are coming from - that DCSG is a pretty high-end piece of equipment and likely the profiling software you are using as well. It's therefore reasonable to expect you are getting higher quality profiles. Interestingly, the steps I recommended to Chadd appear to have retrieved enough highlight information to be usable, so again, I'm just not sure that profiling is his issue, though for sure worthwhile exploring.
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Mark D Segal (formerly MarkDS)
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Stephen G
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« Reply #12 on: November 04, 2012, 01:58:47 AM »
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My V700 workflow is pretty simple:

I use Vuescan and output it's 'Raw' scans. Basically a linear tiff, straight off the scanner, no adjustments of any sort. Don't know if Silverfast can do this, maybe its profile generation uses a similar raw scan. Mark? Also: can Silverfast make use of the DCSG as a target?

I used Profilemaker to generate the profile from a raw scan of the DCSG. (Didn't buy one myself, just rented it for a day about $20 equivalent and have been using the profile very happily for ages now.) Free alternative to PM would be Argyll, but needs lots of messing around before you get good results.

Assign profile to scans made in exactly the same way as the target scan. Tone and, depending on the pigments being scanned, colour pops nicely. 95% of the work done. One or two hard proofs and minor tweaks get an excellent match.

Something I just stumbled across two days ago: CoCa  It's a very friendly front-end for Argyll camera profiling but you can use it for scanners too, if you select the right algorithm. I played with it for a few hours on Friday morning and early results suggest that the profile quality is better than PM5. Haven't used a CoCa profile on a watercolour painting job yet. For the DCSG I had to use an Argyll-friendly version of the reference file that comes with PM5 here I used the tiff from here to compare profiling results. just layered them and used difference blending.
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Mark D Segal
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« Reply #13 on: November 04, 2012, 07:52:42 AM »
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Hi Stephen,

Yes, SilverFast has been able to output a "raw" scan for a very long time now, in the sense of a linear TIFF with no adjustments made. You can use any scanner profile you wish as the Input profile with SilverFast; however SilverFast' Auto IT8 profiling process will itself only self-generate profiles using LSI's supplied targets, which are bar-coded and accompanied with their own reference files. Using this process one doesn't need other targets or profiling software, but of course it is limited to their own materials.

The procedure you describe is obviously a lot more work, but very interesting if it's delivering better profile quality that makes a difference for certain kinds of output.
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Mark D Segal (formerly MarkDS)
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« Reply #14 on: November 04, 2012, 08:36:13 AM »
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Stephen, recently I also tested CoCa to profile my scanner using its 16 bit linear output.  See this thread: http://www.luminous-landscape.com/forum/index.php?topic=71953.0 

Which algorithm did you find worked best for your scanner?
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Dean Erger
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« Reply #15 on: November 04, 2012, 09:52:32 AM »
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It was one of the 'clut' algorithms, I think, but can't recall right now. The tests and profiles are on my work machine which I'll get back to tomorrow morning. (about 15 hours from now. I'm on GMT+2)

Like I said I've only played with it for a few hours - very limited testing, but it does look very promising.
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dmerger
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« Reply #16 on: November 04, 2012, 11:36:50 AM »
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Stephen, please keep us informed on your progress with CoCa.

I just created another profile with CoCa.  This time I used the LAB algorithm, whereas before I used XYZ.  I started with the same scan of my Provia IT8.7 target, used the same target reference file, and all the other same settings in CoCa, except to change the algorithm.  Once again, however, as described in my the thread I linked to above, the profile was exactly the same as all the others I created with CoCa.  Something is seriously amiss, but I have no idea what.  CoCa is so easy to use, but maybe something I'm doing is messing up the profiles, or maybe something is screwed up with CoCa.  Very puzzling.

EDIT:  I just made a similar profile using the Gamma-Matrix algorithm.  This one is slightly different than the others.  So, maybe I'm actually doing everything correctly?
« Last Edit: November 04, 2012, 11:53:35 AM by dmerger » Logged

Dean Erger
chaddro
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« Reply #17 on: November 04, 2012, 05:16:02 PM »
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This is very interesting... I've played with Argyll some, but since I've been mostly using Epson's paper's with their canned profiles I've been pretty happy. I'll take a look at Coca too.

Here is one of the stamps I was working on. Original size, and a crop from the large print. I think my client will be pretty happy with the results. It was just crazy wanting to make a 30" prints from 1" high stamp but I think I pulled it off.  Really appreciate the help here. My post over at Siverfast still has been approved. No wonder their forums are so dead.

Mark, is there a general purpose IT-8 target that you would recommend? Do I need different targets for reflective and negative profiling?

I have a big personal project coming up. About 300 negatives from some 50+ years ago. The prints were destroyed in a fire. It is a large mix of 35mm color, b/w and these large square negative (mostly b/w).

Stephen, I do have PM5 so I can give the DCSG a go and try my own profiles. One question though: does the profile replace the scanner profile in silverfast, or does it get applied to the image in photoshop after scanning?

-chadd

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Mark D Segal
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« Reply #18 on: November 04, 2012, 05:37:05 PM »
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Hi Chadd,

Firstly - remarkably good results. I'm really pleased you got that detail and clarity as well as you did. It speaks well for both the scanner and the operator.

I guess you meant to say your post at SilverFast Forum has NOT been approved?

There is no such thing as a general purpose IT8 target. There are Kodachrome targets, non-Kodachrome positive transparency targets and reflective targets, each for their own media type. Kodachrome targets by the way are just about impossible to find outside LSI and they are getting scarce there too, because the stock cannot be replenished. No more Kodachrome and no more Kodachrome processing labs, but no supply problems for non-Kodachrome targets, be it from LSI, Don Hutcheson or others.

There is no such thing as IT8 scanner profile targets for negatives. For negatives, in SilverFast you would use Negafix. My book goes into detail about that for both colour and B&W, but I also published similar content on this website about scanning negatives before I undertook the the book project. www.luminous-landscape.com/tutorials/silverfast-scanning.shtml and http://www.luminous-landscape.com/techniques/scanning_colour_negatives_raw_or_not.shtml. All this predates SilverFast 8 but the principles are pretty much the same.

For 35mm colour negs, if you can get your hands on a really good dedicated film-scanner such as a Nikon 5000 or similar, it will likely deliver a sharper result than the Epson V700. The V700 however is very good for the larger format negatives (for example 6*6 cm and larger).

I believe Dean, who has been participating in this thread, if I remember correctly has also been quite successful digitizing film using a camera instead of a scanner, so he may well pitch in here.

As always - choices, choices, choices.
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Mark D Segal (formerly MarkDS)
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« Reply #19 on: November 04, 2012, 07:56:21 PM »
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Hi Chadd,

I should have mentioned - if you would like to see some samples of colour negatives I scanned in SilverFast using Negafix and converted to B&W, some with and some without application of effects (toning, colour accents), you can have a look here http://www.markdsegal.com/angkor/. The scanner used at the time was a Minolta Dimage Scan Elite 5400 (dedicated film scanner) - again one of those excellent pieces of scanning hardware that was discontinued. While you are on the site http://www.markdsegal.com/, the galleries of Vientiane and Bangkok-Wats are also from scans of colour negative film done in SilverFast with the same scanner.
« Last Edit: November 04, 2012, 07:58:33 PM by Mark D Segal » Logged

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