Color Correction with DSLR Scanning?

adamr1699

adamr1699

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I have recently switched to DSLR scanning instead of a flatbed. I have been getting great results in sharpness, contrast etc. I have been shooting raw and editing in lightroom. the only major issue I am having is with color negative film, getting the colors right. I've heard of Color Perfect which has the presets for different films.

What do you guys use/ do to get the colors right what scanning color negative film?

Thanks all!
 
Colour never is just difficult I think. There are several aspects:

The orange mask is actually a density dependent mask and not constant. There are a couple of places on the web where removing this is discussed, using calculations in photoshop.

To get 'accurate' Colour's you may need to think of how the negative is transformed into a positive print in the process - the dyes in the print paper don't necessarily invert the Colour's in the neg.

The process isn't reallly colour accurate anyway.

Best to go with something pleasing and try to avoid colour casts I think.

Fwiw, I currently scan colour neg with my dslr, a cc30m gel and a cc30b gel to even up the sensor channels a bit, then invert in photoshop and am starting to play with assigning output colour spaces.

Mike
 
I have used the Color Perfect filter in Photoshop to convert DSLR images of C41 color negatives, and it does a good job. I won't say perfect job, but it gets you most of the way there. It is a whole lot easier than trying to adjust the inverted image's colors by manual sliders in Photoshop.
 
The easiest way for me was to download the photoshop action from Michael Fraser. Also read up on it. I used to use colorperfect when i was doing epson, but when I tried it with DSLR method I didn't like it.
visit this link
 
I have been working on Color negative as well.

I had several theories about what was causing the problem. I now conclude that the non-linearity of film is the primary culprit... I can get good dark grey and light grey, but the tonality is wrong.

Here's my current recipe that produces good results, as good as the mini-labs I used to use:

- Shoot RAW, make sure the exposure fills the middle of the histogram, avoid both ends
- Run the RAW file through MakeTIFF
- Then ColorPerfect filter in PhotoShop. This handles the non-linearity. You can specify the brand and type of color neg film in ColorNeg.
- Back in PS add a Curves adjustment layer. Do Option-Auto and select "Find Dark and Light..." and "Snap Neutral Midtones"
- That gets pretty close. After that, I'll do my usual PostProcessing adjustments.

IHMO, Color perfect is well worth the $67 price tag.

Hope this helps. Post your results!
 
An alternate workflow with PS but not ColorPerfect that does deal with the non-linearity of negative film: See this thread

Download this custom inversion curve provided by @jzagaja (Jack, a participant here)

1) Log curve: https://drive.google.com/open?id=0ByP8kkW_h00uelltOC10a2N1Vlk

Then the steps are:
- Shoot RAW
- Open file in LR or PS
- Neutralize the orange mask with eyedropper on an unexposed film area
- Crop to the real image area
- Add a Levels adjustment layer, make the histogram fill the center, stay away from the edges
- Add a Curves adjustment layer, use @jzagaja's custom curve which will invert the image
- Add a Curves adjustment layer, Option-Auto, "Find Dark and Light..." and "Snap Neutral Midtones"
- Further adjustments from there.

This post has a good example shot.
 
p.s. I was experimenting with using a DiChro head to illuminate the negative with Cyan/Magenta light to offset the color mask.

I think that helps, but the non-linear inversion (ColorPerfect or Jack's curve) was far more important.
 
Scapevision said:
The easiest way for me was to download the photoshop action from Michael Fraser. Also read up on it. I used to use colorperfect when i was doing epson, but when I tried it with DSLR method I didn't like it.
visit this link
Click to expand...

I've experimented with this action set and studied the linked page.

The action is pretty handy; sets up four adjustment layers.

The "invert" layer is a straight Photoshop Invert, which I don't like. You can see the result in my example linked above.

The "Tone Correction" layer gave me the hint to try Option-Auto with "Find Dark and Light..." and "Snap Neutral Midtones", and this I think is a break-through.
 
Saw some DSLR scanning threads earlier here, but now actually stumbled into one. Photoshop layers and actions, editing raw etc. This is more hardcore digital than digital! :)
 
Here's What I Do

Here's What I Do

I Use VueScan and Photoshop CC

• Scan as RAW
○ set Multi Exposure (passes =1)
○ set Mode, Medis Bits per Pixel (48), Resolution
○ make Preview
○ set Skew and Crop
• Save Raw to HD
○ Save as Vuescan raw DNG
○ Raw Output with Scan (does not apply grain or IR correction to raw)

Processing In VueScan
o Use Raw File stored on*HD
- Change Viewscan Source to File
○ preview, as image
○ virtual scan and adjust as needed, rescan (virtually) to affect changes
○ save as Tiff DNG in for import to LR or other image rendering software

White Balance For Color Negatives in Photoshop (This is my preferred method)
○ Invert it.
○ Use manual mode
○ Set Histogram to Log
○ Adjust Natural RGB and RGB Brightness sliders such that the RGB curves interact at the same point (or overlap) on both edges of the histogram

• Alternate White Balance Method (I never use)
○ Invert it.
○ Bring the orange negative into photoshop.
○ Create a curves layer.
○ Go to the red channel and alt-click on the black slider and move it until it just starts to clip or slightly before that. Do the same for the white slider.*
○ Then do that on the remainder of the channels.
○ The center adjustment slider below the histogram controls contrast
 
William, with a scanner and Vuescan, do you invert the image to positive in Vuescan? Or take the orange negative image into PS and invert it there?
 
Col.

I believe I invert in Vuescan.

I don't think it matters for flat files (VueScan raw DNG or TIFF). Inversion is non destructive.
 
Thanks William. I'm betting that the "invert" process in Vuescan, transforming a color neg to a positive, is non linear.

My bet: Vuescan, ColorPerfect, and "Jack's Curve" are all non-linear.

Different from Photoshop's "Invert" which is linear.

My further bet: The non-linear inversion is what we want for dealing with a scan or camera-scan of color negative material.

When I invert in Photoshop, I can get a passable positive image, one that I can work with, but the tonality is off. I get better tonality and color by using one of the non-linear inversions.
 
Michael Frasier plugin

Michael Frasier plugin

When I click the link to the Michael Frasier plugin, I get a blank page saying the website has expired. Anyone know another site to get the plug in?
 
Color Perfect was my answer too. It was hit and miss before they came out with Make TIFF. So, convert your raw files with Make TIFF to a stripped TIFF file of all interpretation from the camera. And then open them (the stripped TIFF file) in Color Perfect's Perfect RAW.
 
Filter the light using a plain frame with no image so as to make color cast disappear.

You will find the mask consistent for a brand and slight variations in batch to batch for color layers.

Make an action to invert the image and then color balance by using levels on individual color channels. Actions can be made to stop at points for manual intervention. Or try auto level on each channel. But manual always gets perfect color.
 
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