Red 35mm Slide - How to Color Correct?

[lamboe80]

My grandmother has hundreds of old 35mm slides that she has asked me to scan for her. I've discovered that almost every slide is overpowered with red. I have been able to successfully color-correct everything up until now. This slide is giving me fits, so I thought I would see if anyone here can help out. I've tried curves, color balance, and all of the other steps that I've used on the other slides I've corrected. I think this will require editing the channels, and I have no experience in doing this. Can anybody help?

[Doug Nelson]

Instead of editing channels, try using a levels adjustment layer. Keep it open and set the dropdown to red, then hold down the alt key and drag in the white and black sliders until you can just see detail starting to show. Then repeat with blue and green (all with the dialog still open). Then go back to each channel while you're looking at your image on the screen and move the middle slider. Once you get this zeroed in you can just drag that adjustment layer over to another open image and it will be automatically applied.

(I'd be obliged if someone would write this up for our Tutorials section)

[Cameraken]

Hi Lamboe80

Doug’s method works great for the colour but it introduces a lot of chroma noise.

I used the black channel for the luminosity, Sharpened it and evened out the exposure corners.

There is still some painting to do to paint out the noise.
I used blank layers set to color to paint

If you want the numbers, just ask

Hope this helps.

Ken.

[lamboe80]

Thanks Ken! That's loads better than I was able to do. Could you give a few more details though?

[mistermonday]

Ken, nice job. However, hand painting a ton of images will be very time consuming. This image is particularly challenging because if you examine the Green & Blue channels there is virtually no data. Most of the pixels are dead 0 (black) and what data is there tops out around 30. Levels and curves won't cut it because all they will do is introduce random noise. So the approach I took was to bulk rebuild the G&B channels.
- Using Apply Image, apply the green channel to itself inverted and 50% opacity.
- Same for the Blue channel.
- Phot filter layer next to get a skin tone balance.
- A little blue and green color fell in by default
Now you can leave as is or do some selective painting or toning.

Lamboe80, I hope all of your slides are not this bad. Did you use a flatbed scanner w/ adapter or an actual Slide scanner with a high dynamic range?

Regards, Murray

[Doug Nelson]

I suspect if you try my technique on the fullrez scan, you won't have the noise problem.

[Cameraken]

Hi Lamboe80

Thanks for your comments.

I realise you have a lot of these and Murray’s method may be better. It just depends how much you want to do.

I split the job into two parts. One part to get the luminosity (B&W) and another to get the colour.

I opened the image and duplicated it. I converted the duplicate to CMYK

On the RGB Image

I Adjusted levels as Doug suggested. I used these numbers
Red 29 0.77 224
Green 0 3.23 49
Blue 0 1.36 74

This improves the colour but introduces a lot of chroma noise (green spots)

On the CMYK Copy

I copied the Black Channel to a layer
Adjusted Levels
Added a layer set to Overlay and painted in white to adjust the exposure in the corners of the picture
Sharpened
I then copied this Black layer back to the RGB image and set the blending mode to luminosity


We now have an image with colour from the levels adjusted RGB and the luminosity from CMYK Black.


I added layers to paint out the green Chroma Noise and improve the colours


That’s about it. You may also like to try Neat Image to reduce the noise even further.

I hope this helps. I have attached my layers. I am sure most of this could be made into an action and as Doug has mentioned the noise may not be as bad in a hi-res copy.



Ken.

[lamboe80]

Lots of great tips here everybody. thanks for your efforts.

Murray: Yes, the green and blue channels are severely damaged. they have faded away almost completely. That is what is giving me the most fits. I like your approach, and I will give it a try.

Doug: I tried your approach on the full rez version and still got dreadful results. Your approach works perfectly on all of the other images I have with the red cast. This slide in particular just isn't cooperating.

Ken: Thanks for your detailed explanation. I'll try your approach as well.

[Flora]

Hi,

working with the size and resolution of the image posted, to prevent the chroma noise Ken was talking about, I 'edited' the green channel which, in my opinion, was the worst of the lot..).

Here are the 3 steps I took to get to an 'acceptable' result:

(Working on a duplicated background Layer)

1* Duplicated the Red Channel, run Levels on the duplicate to improve tone and contrast a bit, copied it and pasted it on the damaged Green Channel. (Attachment 1)

2* Back to the Layers, (Attachment 2) I used a Levels adjustment Layer (tweaking composite RGB and Blue) on the 'horror' achieved with my previous 'correction' .... B&A Levels (Attachment 3) ....

3* To correct the colours, I used a Selective Colors Adjustment Layer with the following values:

Reds:
Cyan +65
MAgenta -31
Yellow +38
Black -24

Yellows:
Cyan -27
MAgenta +8
Yellow -31
Black +28

Magentas:
Cyan +42
MAgenta -100
Yellow +81
Black -23

Whites:
Cyan -9
MAgenta -15
Yellow +43
Black +7

Neutrals:
Black -18

Blacks:
Cyan +7
MAgenta +1
Yellow +19
Black -9

Result after Selective Colors (Attachment 4).

After this, it's a matter of how much or how little you have time to do to finish the restoration... (Attachment 5 > my final restoration)

[mistermonday]

Flora, AWSEOME!! You are still the Godess of Color Correction.
Regards, Murray

[ahmetturker]

Great works bravo. Cameraken & Flora. !!!!!!!!!!!!!!!!!!!











.

[plugsnpixels]

Excellent work, Flora! That was a nasty image indeed.

Just for fun I tried several major color-correction plug-ins (1-click as well as slider types) and couldn't get close to what you did manually with most of them . The best I could do was with Color Washer, followed by slight refinements in iCorrect Edit Lab.

Advantages: Much faster--a few clicks and slider adjustments.

Disadvantages: You have to buy extra stuff...

It's the eternal choice when editing images (either speed or savings).

[Pam]

Flora,
That was amazingly, breathtakingly stunning!!

--
Pam
http://www.pbase.com/pam_r
'art is working on something 'til you like it...then leaving it that way'

[Daviskw]

Good work all.... Flora I don't know how you keep track of all your steps.

I know for my version I used shadow/highlights on the red channel copy and replaced both green and blue channels.

From there I used mostly Hue/saturation and curves adjustments. I did not have much luck with selective color.

I did I think get it at least acceptable but could not list my steps.... I went back and forth too much.

Sure would be nice to know the true color of the couch... notice how every rendition has a different hue. If a retoucher knew at least one color for sure I think it would be easier to correct.

Butch

[Flora]

Murray,

thank you so much for your kindest comment ... actually I'm a bloodhound ... meaning ... I don't let go until I get a result I can accept, or I completely lose the 'scent' ...

ahmetturker,

If I haven't done it yet, welcome to RP!!

thank you so much for your kind feedback!!!

plugsnpixels,

thank you so much for your kindness!!

Originally Posted by plugsnpixels

Advantages: Much faster--a few clicks and slider adjustments.

Disadvantages: You have to buy extra stuff...

It's the eternal choice when editing images (either speed or savings).

... Right!!!
Personally, I have very few extra plug-ins ... I enjoy trying to find ways with PS which, in my opinion, is still the "Ferrari" for image manipulation ...(I'll probably get shot for this.. ) ... But PS is only a hobby for me, so, I'm never under time pressure when I work with it ... I'm sure that if I were a professional restorer/retoucher, I'd probably appreciate speed...

Pam,

thank you so much for your kindest comment!!!

Butch,

thank you!

Originally Posted by Daviskw

Flora I don't know how you keep track of all your steps.

.... Well ... in this case it was just 3 of them... ... Kidding aside, I simply keep them all ... meaning:

• Instead of applying the corrections directly to the Layer, I work with Adjustment Layers .. this way, I can always go back (step by step) not only to change things, but also to check what I tweaked in a particular AL (Levels, Curves, etc.) and which values I used or changed...
  
  
• I always Merge Layers by making sure I've activated the topmost visible Layer and keeping the ALT key pressed while 'Merging Visible' .... this procedure creates a new Layer containing all the corrections done so far on top of all the other Layers without 'flattening' the image ... that means that I can go back to each step I took before merging...

This keeps me from asking myself: how on earth did I do that?? ... and allows me to give detailed explanations (including snapshots) of each step I took working on a picture even if asked weeks after having posted it...

Were it not for these procedures, (you need a very large HD for this..) I couldn't remember a thing ....