Poor de-cyan

[Charles Twist]

Hello everyone,
I come to you looking for negative comments...
Following on from the demise of Astia and the recommendation of negative film, I have tried my hand at Kodak 160 NC for my architectural work. It does a brilliant job with the dynamic range. The problem I have is with the conversion to positive colour - a process which has to be painless to be useful. It seems that even with the greatest care, I always end up with a hefty cyan tinge. I can fix that to some extent with 'Replace Color' in Photoshop. But I find it surprising that even with dedicated converters like ColorNeg, I end up with areas not registering any red. These areas cannot be corrected because the information is missing entirely. I can tweak the colour of the whole image and bolster the red channel, but it has no effect on the problematic region and a deleterious effect on the rest of the picture. Am I alone in this?
I am also finding that ColorNeg is not a cure-all. In the picture below, it got to within spitting distance and I was able to tweak it with 'Replace Color' (still needed to shift the cyan hue by 25 degrees!), but Photoshop on its own got nowhere near. With other pictures, ColorNeg was just a mess and Photoshop tools were more efficient - notably Levels. Before I spend my money on ColorNeg, is there a better Photoshop method which works 99% of the time? Is it just the colours in this picture which are causing havoc? I suspect that the subject's colours are making life murder in this particular case. If anyone fancies the challenge, I attach the file to play around with in Photoshop (you'll need to convert it to 16-bit to play with ColorNeg).



The gridlines are due to ColorNeg in its trial version. And there does seem to be some flare on the LHS - not sure where from.

Thanks everyone for your help. Regards,
Charles

[jb7]

I find red difficult, but not impossible-

I've only used the NC once, but I didn't have the problems you describe-



I also took this on Digital, and the film scan was far more accurate-
This was on a V750 using Silverfast-
I don't know of the programs you mention.

It's always difficult to tell on a monitor, but the print of this wasn't bad-
the velvety texture of a rose is very difficult to photograph, at least for me-

[Patrick Dixon]

I haven't tried it, but one suggestion is to shoot a frame of pure black and pure white (and maybe mid-grey) under a similar colour temp, and use that as a reference to set the black and white points on your target frame using PS curves. I guess you could then use PS colour filters to adjust overall colour temp.

Nice roses btw, jb7. A gift for Valentine's Day?

[jb7]

just for you, Patrick-

Timing is everything...

[Dave Tolcher]

Not a direct answer but I really struggle with Silverfast and 160S - I have found that using epsonscan gives a much better scan and particularly colour - click auto and then adjust levels to correct the issues but colour is OK. Have you tried vuescan instead as an alternative ?

[Charles Twist]

Apologies for intruding on such a tender moment, but...
Thanks for the roses, which, I am afraid display the problem to which I allude. The petals are nice, but the leaves seem out. I took the liberty of copying your image and doing a "Replace Color" to remove the cyan tinge from the leaves.



Do you agree with me, or am I deluded? My impression is that the sky in my pic was too green, and your leaves were too blue. So if I am right, I am inclined now to believe that the handling of colours made of blue and green is delicate and tends to fall in a cyan rut.

I haven't tried Vuescan, but the Epson software has fared well so far. It seems that one needs to buy the full version of Vuescan in order to create Raw files which Epson produce as a matter of course. I'll read up the reviews.

Regards,
Charles

[scovell001]

Would this document help - http://www.hutchcolor.com/PDF/Cneg.pdf

[scovell001]

Charles,

I've had a bit of a play around with your negative image, and I'll happily admit ,"it's kicking my arse". Thats a nasty one. Is there a way you could include part of the neg border in the scan so I can have a crack with Don Hutcheson's C-Neg scanning.

Best


Ian

[Patrick Dixon]

Ian, that's an interesting read - thanks for posting the link.

[Charles Twist]

Hello Ian,
I am struggling a bit with the forum software at the moment - Joanna blames my computer - so apologies for not posting a response successfully yet. Using a combination of those documents, Joanna's comment on the Levels thread and some thinking & tinkering, I have achieved this:



Which is quite close to what I wanted. The red is certainly very strong - I actually desaturated by 20 to accommodate the sensitivities of the tender souls on this forum. I am glad it was Kodak NC not VC. My general feeling is that removing the tendency to cyan without affecting the magenta component of red colours is quite tricky, and tends to be noticible when there is a lot of red, obviously. The red in this picture is very tricky because of the many different tonalities: direct light, light reflected off the building behind me and light from the blue sky.
I'll post you a scan to play with: it'll be interesting to see what you make of it.
Thank you everyone for your help,
Charles

[scovell001]

Charles,

Thanks for sending the image through. I've posted it here for you/all to look at. Now, firstly, you need to remember I don't know what the building/walkway looked like so I've just gone on your versions posted in this forum.

Right, what I did was set highlight & shadow using levels & the alt key held down to show clipping. Rather than do this on the RGB channel, I did it for each channel individually, which is a known method for killing colour casts. I also adjusted the gamma (the mid slider) whilst I was setting the highlight/shadow in the red & blue channels very slightly to tweak the cast out a little more. Finally, I did a hue/saturation adj layer & took a bit of green out the walkway & increased the saturation in the reds.

Does it look O.K.? I'm not 100% on the colour of the walkway, should it be a pure grey? The red changes to blue/turquoise up the building, but could this have been caused by a colour influence in the sky?

Anyway, thats about as much time as I've got to spend on it.

Best


Ian

[timparkin]

Hello everyone,
I come to you looking for negative comments...
Following on from the demise of Astia and the recommendation of negative film, I have tried my hand at Kodak 160 NC for my architectural work. It does a brilliant job with the dynamic range. The problem I have is with the conversion to positive colour - a process which has to be painless to be useful. It seems that even with the greatest care, I always end up with a hefty cyan tinge. I can fix that to some extent with 'Replace Color' in Photoshop. But I find it surprising that even with dedicated converters like ColorNeg, I end up with areas not registering any red. These areas cannot be corrected because the information is missing entirely. I can tweak the colour of the whole image and bolster the red channel, but it has no effect on the problematic region and a deleterious effect on the rest of the picture. Am I alone in this?

Thanks everyone for your help. Regards,
Charles

Hi Charles,

Without knowing what it would have looked like (which I doubt you can conjure up from memory with the combination of blue sky, green grass and red building all influencing the walkway for instance) I would say that the first conversion you showed looked fairly good. The red colour you converted too looks more like a velvia/provia version to me. The only real way to get a grip on whether you are close would be to take a digital colour balanced reference shot just to check (you could get away without the colour balance if you wanted a general guideline).

I have a feeling that the coatings on the window are adding a green tinge to the blue sky reflection and that the walkway is picking up the blue sky combined with the red diffuse light from the building.
Could the magenta be a mixture of building red + sky blue?

Any chance you could go back and take a digi snap in equivalent conditions?

Tim

p.s. Did you get the right value in scantiqe

[scovell001]

I think this is a good of example of 'why not' shoot neg film. Its just a pain in the arse when it comes to digitizing.

[Patrick Dixon]

Yes, but OTOH it does allow for a more artistic approach to colour photography than often seems possible with transparencies. I can't help feeling that AA would have been happier with colour if he had had colour neg film, scanning and photoshop available to him.

Any of the conversions above are fine - it just depends what you're looking for. Had it been shot on transparency, you'd have been hung-up on what the transparency looked like, and stuck with the colour characteristic of the film.

[Charles Twist]

Firstly, big thanks to Ian for his help.
Secondly: the picture. Tim: you're spot on about the colour of the scene. I had mentioned that as a problem to Ian in my off-line email. The colour of the walkway is anyone's guess in real-life. However, I know it is painted white and indeed my brain's auto white balance perceived it as such. So ideally, that ought to be the final colour. The wall behind me is black; there was direct light pinging off the red wall onto the black wall. The sky had few clouds. As indirect light from the sky works down the space between the walls, it loses blue-ness and gains red-ness, as can be seen in the degrade.The green windows are probably not much an issue as I guess more light goes through them than bounces off them - being windows and all that (I admit they might be designed to reject a lot of green light for some reason). The wall in front of me is distinctly red - almost a prime red it feels - so the more saturated version is not such an issue, although not everyone's cup of tea. I found this in the local paper, which shows you how red:



I wonder how that would come up on Velvia 100?
I thought this picture would be a challenge for the dynamic range, but it's on the colour that it is floundering. In order to create a reference point, I could also include in the shot a prepared black, white and grey card or create a second exposure with it in.
What I do like about the variety of processes and results is that I can adapt the rendition to the brief. Whatever the client wants, they get. I agree with Patrick on this. Colour neg gives freedom, with which comes the burden of decisions.
Any more comments are welcome.
Regards,
Charles