Copying color negatives with camera

Luisifer wrote:

Nice to read that my thoughts are going in the right direction. See thread with a smaller digitization project here:
http://www.dpreview.com/forums/thread/3680724

It is about larger formats but it is still the film material (bw, color inv, color neg, doesn't matter).

My maximum will be macro 5:1 (about 20 kDPI) with the assumption of the resampling to the 4 kDPI. 25 times smaller resolution as the result versus initial digitizing.

Expectations are not only about details in drawing but higher bit depth result (in the best case in some larger color space). Especially so big hight bit dept that resampled result will be better than RAW format from any of the DSLRs.

I wouldn't be able to obtain a 5:1 ratio unless I use a 28mm prime lens on my bellows. I wonder if corner sharpness will be an issue? I use Minolta SR lenses. The only other issue I can think of is that on some of my pictures I have blue sky with no clouds, which might be a problem for a stitching program.

I recently inherited a large collection of family slides and negatives from my grandfather. I haven't had the opportunity to go through all of them but I know that some are medium format, others are larger about the size of a 4x5 index card. A 5:1 ratio just sounds like too much effort to do for large negatives.

AdHoc007 wrote:

3) By a long long way the best results will be obtained by pre-filtering the lightsource in such a way as to get a capture that matches the native colour characteristics of the cameras sensor and accounts for the colour temperature of the lightsource and the films mask characteristics. This is pretty tricky to do, involving quite a bit of testing but the differences in the final result are like chalk and cheese and the resulting files are far easier to edit.

So I would probably be better off with filtering the flash head with some gel filters that can color correct for the mask? What kind of filters? I've glanced at some color enlarger heads on ebay and they seem to use a combination of yellow, magenta and cyan filters to balance out the light. Are those kinds of gels sufficient?

I suggest a colour correction filter such as an 80A.

Try Lee filters for an acetate one.

Lots of great information here -- thanks again to the OP and other contributors (also, apologies to the OP for any hijacking).

AdHoc007 wrote:

The only other issue I can think of is that on some of my pictures I have blue sky with no clouds, which might be a problem for a stitching program.

Maybe you could use landmarks on the outside of the frame (like the tractor-feed holes of the film) for the stitching.

I'll be very interested to see your results with filtered light.  I don't think I'd go to that trouble of experimenting (I don't have any masterpieces from my film days), but I could totally see copying someone else's tried and true results!

With the stitching of the similar "puzzle" pieces .... I have experience that SW try to insert pieces anywhere (and it is wasting of time). This part of "task" i didn't test yet, but it is not a good way "allow" to SW this kind of solving the stitching.

I expect some kind of text log where will be names of files in right order in matrix and stitching SW will strictly hold this order.

After some promising preliminary results, I put together some hardware for digitizing my negatives.  Rather than hijack the thread, I made a new post with a link back to this one.

Thanks again to the OP for providing results that made me hopeful enough to try this.

Just an update, awhile ago I ordered a swatch book from Rosco, which has a huge variety of filters, most important were the ones in the cinegel package, which had neutral density, and color compensation filters for every combination of Red Green and Blue.

So now my workflow is to first, use a negative of a picture that was properly exposed, take a picture of it and have the white balanced set to a fixed number, I'm using 5000k, I'm not sure what Kelvin my flash is. After taking the picture I go back to my computer and look at the histogram to see if the Red Green and Blue histograms are all in alignment. If not, I simply find the appropriate combinations of gel filters from the swatch book, place them over the flash.

My flash had an insert for filters, and it was the perfect size with the swatch book gels, accept, the heat from the flash was hot enough to warp the gel, instead I put them over the flash.

I just want to throw an idea out there for the color filtration. Couldn't you try an older color enlarger? It would have a light source, a color filter head that you can dial in the amounts of magenta, cyan and yellow. Then you have a negative holder that is clamped in and perfectly straight. Then bellows then an enlarger lens you don't need. Remove the lens, rig up an attachment for you camera a lens and you're pretty close to what you need. I would think you could pick up an old used color enlarger pretty cheap.

Any ideas if this would work?

Snapshott wrote:

I just want to throw an idea out there for the color filtration. Couldn't you try an older color enlarger? It would have a light source, a color filter head that you can dial in the amounts of magenta, cyan and yellow. Then you have a negative holder that is clamped in and perfectly straight. Then bellows then an enlarger lens you don't need. Remove the lens, rig up an attachment for you camera a lens and you're pretty close to what you need. I would think you could pick up an old used color enlarger pretty cheap.

Any ideas if this would work?

The idea is doable, though I don't have access to an enlarger. They look fairly inexpensive off ebay. I would prefer to use my flash system since it's less space, and the light is stronger than the kind on an enlarger head.

I noticed that on ebay they have color analyzers that are fairly inexpensive, though I wonder how useful they are since a.) The light source I have is most likely not going to be equivalent to the kind in an enlarger head, b.) They are calibrated for photographic paper which is not the same as a digital sensor.

I think right now the system I got of using the RGB histogram in Silkypix and/or Rawtherapee and making adjustments accordingly has given me results that I could be happy with.

You can use CC50 Blue and CC50 Cyan filters (on ebay search for Calumet CC50 Blue and Cyan).  Cost about $40 each.

You want to place them between the flash and the negative (to avoid flare issues).

White balance on a neutral part of the negative.

I'm also working on this recently.
As for hardware part - old slide duplicators work amazingly well. They are available on
ebay for cheap. Just one problem - You need a full flame camera to use them. Otherwise Your scans also will be cropped. Or use duplicators, that mount on a lens.
I just point it to a wirelessly controlled flash and shoot RAW.
IQ is better than any scanner I've ever used - best of them was Nikon Coolscan IV ED. Resolution of Nikon D600 far exceeds the resolution of my films - but have to admit, that I wasn't using high end equipment when I was shooting film.
I process RAWs in Lightroom. Basic thing is to invert the curve - move end points to the opposite sides. It works nice with BW and slides. A bit more complicated with color negatives. I found that LR color ballance slider doesn't go enough to the left to achieve decent result, so I added 80B color correction filter to my slide duplicator. Best color ballance is achieved by clicking on some point, which should be neutral gray. The only thing I couldn't solve for now - redish shadows. Can be corrected adjusting r, g and b curves independently, but it takes too much time. Still didn't find a way how to include it to a preset.

Hi;

This link may be useful to you regarding the theory of what you are trying to do. http://www.hpl.hp.com/techreports/97/HPL-97-16R1.pdf

Colour masks vary according to brand and emulsion type.

The mask is there to compensate for deficiences in the colour dyes in the film (the cyan component being the worst . . . The mask is formed in proportion to the "developed" colour dyes in the emulsion layers - the more image there is the less mask and where the - where is no image  it is all mask. The curves are NOT parallel making correction hard.

If Slide film is processed as a negative the negative image is a nightmare to print because of the absence of the corrective mask. Bad blacks (brwns usually" and crossed characteristic curves making accurate reproduction almost impossible. Photoshop would make this easier , but without a map (lookup table) and some way to interpret it you are working blind.

MAYBE...It might be useful to shoot a grayscale on the negative stock in the light the film was designed for - this would represent a known colour when printed correctly, and scanner software could be used to determine the rgb figures for each step of the grayscale target. Knowing the actual numbers might make it possible to kludge a corrective curve that works.

on the other hand colour negative film fades just as badly and as quickly as colour prints......

Leo "Zoom" wrote:

I'm also working on this recently.
As for hardware part - old slide duplicators work amazingly well. They are available on
ebay for cheap. Just one problem - You need a full flame camera to use them. Otherwise Your scans also will be cropped. Or use duplicators, that mount on a lens.
I just point it to a wirelessly controlled flash and shoot RAW.
IQ is better than any scanner I've ever used - best of them was Nikon Coolscan IV ED. Resolution of Nikon D600 far exceeds the resolution of my films - but have to admit, that I wasn't using high end equipment when I was shooting film.
I process RAWs in Lightroom. Basic thing is to invert the curve - move end points to the opposite sides. It works nice with BW and slides. A bit more complicated with color negatives. I found that LR color ballance slider doesn't go enough to the left to achieve decent result, so I added 80B color correction filter to my slide duplicator. Best color ballance is achieved by clicking on some point, which should be neutral gray. The only thing I couldn't solve for now - redish shadows. Can be corrected adjusting r, g and b curves independently, but it takes too much time. Still didn't find a way how to include it to a preset.

If you use a "full flame camera" you might melt the slide or negative.

Camera Style Refill Butane Cigarette Lighter Jet Flame Torch

You can use crop frame cameras with a slide duplicator attachment; you just need to change the length of the extension tubes used between the lens and attachment. See this article:

http://www.scantips.com/es-1.html

On your X-T1 demonstration, what was the manufacturer of your bellows, slide converter, and, if used, tube extension?  Thank you.

User7448357495 wrote:

On your X-T1 demonstration, what was the manufacturer of your bellows, slide converter, and, if used, tube extension? Thank you.

On my first picture of the setup, I used the following:

Minolta focus rack, and slide copier designed for the Minolta AutoBellows I system. The lens I originally used was a 50mm minolta macro lens that came with a 1:1 extension tube. To get the slide copier to be level with the camera lens, I used the parts from a cheap L-bracket.

I have since moved to the following setup: Minolta Auto Bellows I, with both Minolta focus rack and slide copier. A 60mm Rodenstock enlarger lens, a M39 to Minolta MD adapter, and a cheap knock off focus rack made in China and bought off amazon for 10 bucks.

The newer setup for me is less time consuming to set up and take apart compared to the earlier one in the picture.

Sherwood Botsford wrote:

RE: Colour corrections filters:
Since you are correcting the light before it hits the negative, can't you just use gel filters? They seem fairly cheap on Amazon.

I remember the bad old days that enlargers would have a gel drawer in the head that fit between a heat absorbing glass plate, and the first condenser lens.

not exactly . . . the orange mask is the problem, it is not like a gel filter that paints the entire image with a colour that can be compensated for. As I understood it when I did a lot of work with negative film the mask exists in areas where there is no image developed by the dye couplers which makes corrections with filters not really work. There will always be uncorrectable colour issues as a result. I occaisionally processed colour transparency as a negative for special effects and you wind up with a negative without a colour correcting mask and it is really difficult to make an acceptable and colour correct print using filters because of the missing orange mask which was tuned to work with the paper used to enlarge onto. Brown blacks and crazy crossed curves .

Colour transparency can be copied with few problems by using filters in the light path.... no mask!