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Author Topic: Copy of color film negatives ... Invert possible in ARC?  (Read 14209 times)
TSJ1927
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« on: June 11, 2014, 08:43:33 AM »
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I have been copying old large format transparencies & negatives with my P30+. Transparencies are easy and very good.  Negatives are a bit of a problem to do a RAW process as everything in sort of reversed.  Is it possible to invert in ARC? 
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Schewe
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« Reply #1 on: June 11, 2014, 12:45:17 PM »
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You can use the Point Curve editor to invert the tone curve...it's a bit tweaky. Take the white point and move it down and the black point up. It works well for B&W negs but removing the orange cast of color negs can be a challenge...
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TSJ1927
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« Reply #2 on: June 11, 2014, 06:20:00 PM »
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Thank You Jeff................. that sure gets me well into the "infield".  I used the white point selector as I would in a positive.  Select on the neutral or white area on the negative and the colors were very close.
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KeithR
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« Reply #3 on: June 16, 2014, 05:02:06 PM »
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Since the negative is already a tiff file once it's been scanned into your computer, you might want to try this from photographer Ian Lyons website from a few years back.
http://www.computer-darkroom.com/tutorials/tutorial_6_1.htm
Once you do the initial work of inverting, you could bring it into ACR if you chose to.
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SZRitter
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« Reply #4 on: June 17, 2014, 12:49:18 PM »
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Since the negative is already a tiff file once it's been scanned into your computer...

That is assuming you are scanning. Some of us have turned to DSLR duping to get the negative to the computer.
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rovanpera
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« Reply #5 on: June 25, 2014, 04:12:33 AM »
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the rgb curve is almost last in the order of operations in LR and ACR.

I don't see much use for LR or ACR with negatives, unless you invert them and do a basic color correction in Photoshop first, and then edit the image in LR / ACR after that.
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Stefan Ohlsson
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« Reply #6 on: July 18, 2014, 11:21:33 AM »
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the rgb curve is almost last in the order of operations in LR and ACR.

I don't see much use for LR or ACR with negatives, unless you invert them and do a basic color correction in Photoshop first, and then edit the image in LR / ACR after that.

Have you tried? I helped a museum to set up a station with a digital camera and flash. Very easy and fast way to scan hundreds of color negatives. And Camera Raw makes it very easy to adjust the colors, by first inverting the point curve and then using the automatic tools in the basic adjustments. Not perfect, but for a museum that has to digitize hundreds and hundreds of negatives, the quality was surprisingly good.
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WayneLarmon
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« Reply #7 on: July 19, 2014, 06:29:39 PM »
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Have you tried? I helped a museum to set up a station with a digital camera and flash. Very easy and fast way to scan hundreds of color negatives.

I've been camera scanning color negatives and converting them with ACR/Photoshop for several years.  It is very doable.   I wrote up my procedure on

Camera Scanning your Negatives

The page includes instructions, with lots of screen shots.  And links to the RAW files I converted so you can duplicate my workflow.

Example

Negative "camera scanned" with a Canon 60D.


After converting using the methods I describe, above.


Comparison shot done with a digital camera at the same time the negative was exposed. (Canon EOS-M)

It is very doable.

Wayne
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PeterAit
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« Reply #8 on: July 20, 2014, 07:55:03 AM »
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Doesn't your scanning software have a "color negative" setting that does this for you?
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Peter
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« Reply #9 on: July 20, 2014, 01:55:17 PM »
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Doesn't your scanning software have a "color negative" setting that does this for you?

Peter, there's no scanner (and thus no scanning software) involved here. This is digitization of film via re-photographing it with a sensor-based camera.

-Dave-
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BartvanderWolf
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« Reply #10 on: July 20, 2014, 04:00:16 PM »
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Peter, there's no scanner (and thus no scanning software) involved here. This is digitization of film via re-photographing it with a sensor-based camera.

Hi Dave,

A program like VueScan can read a TIFF and process it as the scan data of a digital negative. Works best with linear gamma TiFFs.

Cheers,
Bart
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Telecaster
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« Reply #11 on: July 20, 2014, 05:36:24 PM »
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A program like VueScan can read a TIFF and process it as the scan data of a digital negative. Works best with linear gamma TiFFs.

Ah, didn't think of that...been a long time since I've used film scanning software (or a scanner).

I remember having good success color-wise with re-photographing negs by neutralizing the orange mask via sampling it & applying the result as an inverse filter. Been meaning to give it a go again with today's higher-res cameras but haven't yet gotten to it.

-Dave-
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WayneLarmon
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« Reply #12 on: July 21, 2014, 02:17:46 PM »
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A program like VueScan can read a TIFF and process it as the scan data of a digital negative. Works best with linear gamma TiFFs.

Yes it can, but I have found the VueScan's results to be mediocre, compared to converting using Photoshop curves.   I just now converted the image I used as an example a few posts ago using VueScan.  Here is how it converted:



This was with VueScan set for Kodak Gold 200 Gen 6, which is the film I used.  (The film was exposed and processed by Dwayne's Photo in the fall of 2013.)



This was converting an image as a linear TIFF exported from DPP (as you advised me to do in a different thread.)  I also tried converting directly from the Canon .CR2 RAW file and VueScan gave identical results, so if you want to use VueScan you can skip converting to a linear TIFF. Just convert the RAW file that your camera generated.

I've tried using VueScan before.  I have always found the conversion results to be enough "off" that I end up spending as much time twisting curves in Photoshop as I do when I convert using only ACR + Photoshop, as I explained in my earlier post.  The time spent in VueScan is wasted time.  Based on the several hundred camera scanned negatives I've converted over the past several years.

Bart, the procedure using DPP + Photoshop on my Camera Scanning your Negatives page was derived from advice you gave in another thread.   The procedure that uses ACR + Photoshop was me ignoring your advice that ACR is incapable of producing a linear file.  In actual practice, I seem to get just as good results using ACR as I do by exporting a linear TIFF from DPP, so I usually use ACR + Photoshop.

I also want to look at Raw Therapee closer.  I stumbled up a web archive of Raw Therapee developers discussing converting film negatives, with the main point being that the current version of Raw Therapee does the same kind of "favors" behind your back that ACR does, which make converting negatives be problematic.  They said that they wanted to add converting film negatives where it belongs in the processing chain.  This thread was from earlier this year (2014) and I haven't looked closely at Raw Therapee since then.

Ah, on this thread they suggest using an inverted DCP (Adobe DNG) profile.  I've tried this and Adobe's DNG editor also does "favors" behind your back.  An inverted DCP profile isn't what you think it is (some colors go hog wild crazy.)

Wayne
« Last Edit: July 21, 2014, 02:20:23 PM by WayneLarmon » Logged
digitaldog
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« Reply #13 on: July 21, 2014, 02:33:58 PM »
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Yes it can, but I have found the VueScan's results to be mediocre, compared to converting using Photoshop curves.
Indeed, quite fugly! The ACR examples are impressive considering how difficult it can be to deal with the orange mask.
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Andrew Rodney
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WayneLarmon
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« Reply #14 on: July 21, 2014, 03:51:43 PM »
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The ACR examples are impressive considering how difficult it can be to deal with the orange mask.


The orange mask sort of goes away when following Bart's advice.  (Direct quote from Bart:)

Quote
1. You need to start with a linear gamma capture.
2. Then adjust the White points (deepest shadows) of the three channels, preferably on inter-image blank film (or un-exposed leader), which will neutralize the Mask color.
3. Then adjust the Black points (highlights) of the three channels to render neutral areas as neutral.
4. Invert tonality, negative becomes positive.
5. Apply tone-curve and color adjustments to taste, for which a LUT can be used to create uniform results.
Copied from this post.

In my rough approximation, a lot of the orange mask goes away when I do a click-white-balance on an unexposed portion of film (between sprocket holes) in the RAW converter.  Then doing the RAW conversion (as 16 bits, in the largest color space available.) Followed by making the R, G, and B channels fill the histograms in PS Levels.  (The closest I can get to Bart's points 2. and 3.)  

Inverting is just Ctrl-I in Photoshop.  Then I go into Curves and drag the RGB curve to adjust gamma (Bart's advice, again).  And Save.   At this point the colors are usually civilized.  But usually aren't quite correct.  I usually go back into Curves and try various Auto options.  And fiddle from there.  After doing a bunch you sort of get a feel about how to twist the R, G, and B channels in Curves.  But the closer you follow Bart's above advice, the better the final image will be.

If you do everything from scratch in DPP (or ACR) + Photoshop, then you reduce the number of curve adjustment on the data.  Each curve adjustment destroys data.   VueScan does a lot of radical curve adjustments as part of its normal operation.

Wayne
« Last Edit: July 21, 2014, 06:03:24 PM by WayneLarmon » Logged
BartvanderWolf
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« Reply #15 on: July 21, 2014, 07:10:09 PM »
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Indeed, quite fugly! The ACR examples are impressive considering how difficult it can be to deal with the orange mask.

Hi Andrew,

The orange/yellow mask is trivial to compensate for, if one knows how to use Vuescan's advanced workflow (which includes total removal of the orange/yellow mask of most negatives). It is everything but difficult, since that's how the mask is designed to dissolve in film-processing. It is an inverse to exposure level mask to improve color accuracy by removing secondary absorptions. Much more accurate color than slide/positive film, and significantly more dynamic capture range.

Cheers,
Bart
« Last Edit: July 21, 2014, 07:15:05 PM by BartvanderWolf » Logged
digitaldog
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« Reply #16 on: July 21, 2014, 07:12:15 PM »
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The orange/yellow mask is trivial to compensate for, if one knows how to use Vuescan's advanced workflow (which includes total removal of the orange/yellow mask of most negatives).
Well sure, it's trivial with any good product designed for this task. I recall how well my old Imacon scanners did this task but there were a few tricks involved. Same experience with SilverFast as well as ColorQuartet I used to drive a ScanView 5000. Never expected this with ACR, that's good news.
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Andrew Rodney
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WayneLarmon
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« Reply #17 on: July 21, 2014, 08:14:31 PM »
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The orange/yellow mask is trivial to compensate for, if one knows how to use Vuescan's advanced workflow (which includes total removal of the orange/yellow mask of most negatives).

Could you be a bit more explicit about the VueScan advanced workflow?  Could you point to the appropriate section in the VueScan User's Guide?

Thanks.

Wayne
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BartvanderWolf
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« Reply #18 on: July 22, 2014, 02:02:22 AM »
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Could you be a bit more explicit about the VueScan advanced workflow?  Could you point to the appropriate section in the VueScan User's Guide?

Hi Wayne,

Here it is: http://www.hamrick.com/vuescan/html/vuesc15.htm#topic12

Cheers,
Bart
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Alexiz
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« Reply #19 on: July 22, 2014, 02:27:00 AM »
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Greetings everybody. I've been reading this forum for quite a while, being interested in the scanning of negatives among other things. Learned much of immensely helpful stuff, thanks to everybody here. But what I've settled on for this particular task in the end is the ColorPerfect plugin which is specifically optimized for this purpose. Was working with VueScan and Photoshop before, but found that the workflow with ColorPerfect was just faster and easier. (There are handy built-in profiles for many types of transparencies; and tools for tuning WB, curves and other things to your liking are actually quite nice in the latest release of the plugin).

It does do a much better job if you scan negatives into linear TIFFs (which I still do in VueScan), and integrates seamlessly now into the Photoshop workflow. I still occasionally do some fine-tuning in Photoshop (post-ColorPerfect, that is); but for most negatives the processing really ends in ColorPerfect now.

(This plugin actually was discussed in the forum before, when it was called ColorNeg -- thought it would be useful to recall it, just in the way of user input...)
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