Post your Trichrome...

[frederic.legac]

I'm just Trichrome beginer... but i like that so much...

5x7 Ilford HP5+ exposed @25 iso and develop 12min in XTOL (1+1)

[billie williams]

I'm just Trichrome beginer... but i like that so much...

5x7 Ilford HP5+ exposed @25 iso and develop 12min in XTOL (1+1)

Very cool!

For others who are waking up on Sunday morning and don't know how it's done, here's a link to a youtube video I found:
http://www.youtube.com/watch?v=S28OUlavAvg

[frederic.legac]

Thanks Billie,

Indeed, It's a good method...

[Mkillmer]

This is not a trichrome - but instead a bichrome - using only Red and Blue filters and synthetically creating a green layer in photoshop - a very weird hybrid of analogue and digital...
This technique is sometimes used in astrophotography www.starrywonders.com/bicolortechnique.html.
Here's an example I made - the colours in the final image were pretty close...
Here is the Blue filter photo:
http://farm8.staticflickr.com/7365/11493284456_0cfe721cc9_b.jpg
and the Red filter photo:
http://farm8.staticflickr.com/7301/11493274006_bcf844705f_b.jpg
and the final version:
http://farm8.staticflickr.com/7416/11493262326_446659abf7_b.jpg

[frederic.legac]

Very good... Nice mood.

[barnacle]

I made the mistake of using a panchromatic film that can't really see red...

145855

Those smaller peppers should be yellow... I'm still trying to get my head around what it is that the gimp does to images. Back in my broadcast TV days, you took an RGB image, tweaked each image for black, gain, and gamma, and lo and behold, everything was wonderful.

As an added bonus, something really rather unpleasant has happened to the negatives; pulled them out of the fix and all three had an odd mottling around the edges. Film taken a week ago from the same batch didn't show it.

Neil

[Chrstphrlee]

Try this earlier thread for some very good information on tricolor.

http://www.largeformatphotography.info/forum/showthread.php?48583-Color-photography-with-black-and-white-film&highlight=tri-color

[Corran]

I've only been really successful at a tri-color once. I've tried a few other times and it didn't quite work out how I visualized it. For what I'm trying to get it has to be just the right conditions, and I don't always carry the proper filters so I've missed some opportunities. This is something I want to pursue further though in the future.

This was taken with my 15cm APO Lanthar on 3 sheets of T-Max 100 4x5, exposures of 15-30 seconds depending on the filters (25, 47, and 58):

http://1.bp.blogspot.com/-JWlDBLGfuy4/VIVFsaxodqI/AAAAAAAAGHY/lDKiyrrPHkw/s1000/colormotionfinished01s.jpg

[barnacle]

Thank you; I was looking for a longer thread.

My background is broadcast engineering. RGB mixing of three (originally four) images is how it's been done since colour TV was invented, probably as an offshoot of earlier photographic work. The separation is made with a prism in the TV camera, with dichroic filters (very narrow bandpass in red, green and blue) doing the colour separation. When an image is combined, it is mixed in very specific ratios: each channel is exposed to give a full exposure range, but mixed in the ratio 0.11 blue, 0.30 red, and 0.59 green to give a correctly-coloured image.

One problem with my image is that there is a processing fault; I think my developer has died the death, causing the edge effect and poor contrast. The second problem is that the filters I used were cheap no-name that I happened to have lying around the place; it's pretty much guaranteed that they are far wider bandpass than they ought to be. A third problem is that I was using up some old panchromatic film which just can't see anything longer than about 600nm...

Neil

[Drew Wiley]

One popular trick is to use 100TMX for the red and green exposures, but 400TMY for the slower blue exposure.

[Corran]

Is that just to keep the same exposure time? I have still struggled with the correct filter factor, usually overexposing the red and underexposing the blue if I follow Kodak's recommended factors. But then I wondered if that was simply due to the difference in actual coloring.