I was just thinking (dangerous thing), I have a colour enlarger - would I need to buy separation filters for the enlarger if I was making negatives for tri-gum from slides or could I just dial in the highest amount of magenta/cyan/yellow to make the red/green/blue filters?
Otherwise I guess I will just be taping on some lighting gel that has nice clean wavelength peaks in the right places...

Akki,
I've been thinking of doing this myself, since I am now venturing into the tri-color gum area recently. Shooting separation negatives with a Lee snap-in filter holder with lighting gels is getting really tedious. I suppose that printing negatives with a color head might work, but would probably require calibrating for just how much cyan, magenta and yellow to dial in to get the equivalent effects from true separation filters. I'd be interested in knowing what results you get from your experiments.

I was thinking just whacking up the magenta/yellow, yellow/cyan, and cyan/magenta up all the way for each separation, since they're not very dense sort of filters. I don't really have any appropriate slides at the moment (only in 6x9cm format which technically my enlarger can't do and I only have 4x5" sheet film so might have a problem getting it appropriately sized & focused) so I guess I have to get shooting and stop putting the cart before the horse :)

On the plus side as far as doing it in camera is that if you have TTL metering, you don't have to mess with different exposure times for the frames, or at least that's my understanding. I don't have a gel holder (or 3 of them for that matter) so that's another problem for me.

I was thinking just whacking up the magenta/yellow, yellow/cyan, and cyan/magenta up all the way for each separation, since they're not very dense sort of filters. I don't really have any appropriate slides at the moment (only in 6x9cm format which technically my enlarger can't do and I only have 4x5" sheet film so might have a problem getting it appropriately sized & focused) so I guess I have to get shooting and stop putting the cart before the horse :)

On the plus side as far as doing it in camera is that if you have TTL metering, you don't have to mess with different exposure times for the frames, or at least that's my understanding. I don't have a gel holder (or 3 of them for that matter) so that's another problem for me.

There is an article from several years ago by Steve Anchel in Camera & Darkroom that describes the process of making a****g seperations using TMAX 100 sheet film. You will need to use the correct color seperation filters as opposed to setting the color on your dichro head.

IMO, there is little reason to do this these days since it can be done so easily in the computer.

Try these,

I use the KODAK WRATTEN
RED 29
GREEN 61
BLUE 47 B

I use them to separate color when contrast masking. They are pretty sharp in their separation.

Good Luck!

Corey

I don't like digital so I'm not going to go that route, thanks. Lighting gel is probably my cheapest route, it's not very expensive to buy half or whole sheets or get my friend to give me offcuts as he's a lampie in the business ;)

I don't like digital so I'm not going to go that route, thanks. Lighting gel is probably my cheapest route, it's not very expensive to buy half or whole sheets or get my friend to give me offcuts as he's a lampie in the business ;)
Lighting filters aren't gel filters, if you go with tri-color seperations on film use Wratten gels over your enlarging lens for best quality.

I was just thinking (dangerous thing), I have a colour enlarger - would I need to buy separation filters for the enlarger if I was making negatives for tri-gum from slides or could I just dial in the highest amount of magenta/cyan/yellow to make the red/green/blue filters?
Otherwise I guess I will just be taping on some lighting gel that has nice clean wavelength peaks in the right places...

If you want to make separations from negatives or transparencies you will need a set of tri-color filters. The correct ones for slides are Wratten #29 (red), #61 (green), and #47b (blue). For negatives I would go with #25(red), #58 (green) and #47 (blue).

Making separations in the darkroom is very complicated work as you will need to balance both density and contrast of the separations for good results. It would obviously be a lot easier to do this with Photoshop, but if you are prepared to put in the time you can get good results with darkroom separations.

Another approach is to actually make the separations in-camera on three different sheets of film using the Red, Green and Blue filters.

Sandy King

I'm having a really hard time finding dark green and dark blue filters for a camera (52mm). I have a green filter and a Tiffen 80A but the 80A is no where near deep enough blue to do anything to change contrast in a picture and the green filter is only a light green (hoya one from the 70s). I can't find wratten filters either. Seems like the doom of digital has totally killed off the filter market (annoyingly)... went into Jessops the other week asking for a blue or green filter and they had hundreds and hundreds of filters - all UV or Skylight! WHY?! I know you need one per lens but... eesh why do you need to keep that many of about 5 different brand/filter combinations in stock?
Hubby has found Robert White might have the Lee one but that's £13/filter. I can buy lighting gel 50x61cm for £4.50. Brand new lighting gel is good quality, it's only if it gets scuffed it'd be much different from a wratten gel.

Also, Sandy, you said "for negatives", does that mean you can use standard c-41 negatives with the orange mask?

I'm having a really hard time finding dark green and dark blue filters for a camera (52mm). I have a green filter and a Tiffen 80A but the 80A is no where near deep enough blue to do anything to change contrast in a picture and the green filter is only a light green (hoya one from the 70s). I can't find wratten filters either. Seems like the doom of digital has totally killed off the filter market (annoyingly)... went into Jessops the other week asking for a blue or green filter and they had hundreds and hundreds of filters - all UV or Skylight! WHY?! I know you need one per lens but... eesh why do you need to keep that many of about 5 different brand/filter combinations in stock?
Hubby has found Robert White might have the Lee one but that's £13/filter. I can buy lighting gel 50x61cm for £4.50. Brand new lighting gel is good quality, it's only if it gets scuffed it'd be much different from a wratten gel.

Also, Sandy, you said "for negatives", does that mean you can use standard c-41 negatives with the orange mask?

Try B&H Photo Video. You can also check ebay. Tiffen should make the filters you need, but they may only come in gels. Plan on getting a gel filter holder for in camera stuff. Of course if anything moves then you will have a blur. I would shoot trannies and print through the seperation filters in the darkroom. That will give you more flexibility.

Also, Sandy, you said "for negatives", does that mean you can use standard c-41 negatives with the orange mask?

The differences between the tri-color filters I specified pertain to band width. For transparencies you need a narrow band-with filter, for negatives and in-cameras separations filters that have a broader band width give better results.

Sandy King

I'm having a really hard time finding dark green and dark blue filters for a camera (52mm). I have a green filter and a Tiffen 80A but the 80A is no where near deep enough blue to do anything to change contrast in a picture and the green filter is only a light green (hoya one from the 70s). I can't find wratten filters either. Seems like the doom of digital has totally killed off the filter market (annoyingly)... went into Jessops the other week asking for a blue or green filter and they had hundreds and hundreds of filters - all UV or Skylight! WHY?! I know you need one per lens but... eesh why do you need to keep that many of about 5 different brand/filter combinations in stock?
Hubby has found Robert White might have the Lee one but that's £13/filter. I can buy lighting gel 50x61cm for £4.50. Brand new lighting gel is good quality, it's only if it gets scuffed it'd be much different from a wratten gel.

Also, Sandy, you said "for negatives", does that mean you can use standard c-41 negatives with the orange mask?
Perhaps you could find a camera like this one.

http://johnsrolleionlypage.homestead.com/Bermpohl_color_nature_camera.jpg

or this one
http://www.eastman.org/fm/mees/m197400283378.jpg


Three simultaneous exposures through colored filters.

those are crazy!!

thanks for posting!

Corey

IIRC the blue separation negative requires extra exposure and development to have the same density range/scale of the other separation negatives. I would suggest a 20 step grey scale is essential for evaluating test exposures?development. I think I used about 60% more exposure and around N+1 development but no guarantee.