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Mustafa Umut Sarac
06-07-2013, 01:11 PM
I am reading Google and found that Dr.Gaspar was the inventor of Ilfochrome paper. I found a article and it was 72 speed RGB turning Wheel movie taking camera invented by Gaspar and his friends. I learned that he was using two color one side and one color other side print film. I dont know but these are not great inventions , even an school boy could invent them.

What was his major discovery ? What makes Ilfochrome print so jewel like ? What was the relation with RGB Movie and Ilford paper ?

Umut

DREW WILEY
06-07-2013, 01:42 PM
Gaspar invented a working dye-destruction (chromolytic) print process. Some of these prints still exist in beautiful condition. But there were
several major refinements involved before Ciba commercially revived the concept decades later. So technically, he did not invent Cibachrome
or Ilfochrome, but was one of several people working in a predecessor mode. Basically, the medium was saturated with particular dyes during
manufacture, then exposed in the direct-positive mode & developed, after which a strong acid bleach removed the unwanted dyes. This is
entirely different from negative exposure onto chromogenic papers, with the dyes being chemically formed during the chemistry steps, or the
contemporaneous "assembly" color processes like carbro and dye transfer. There is a lot of interesting history behind all this - but I'm certainly no scholar on it. RGB is simply the additive exposure mode, used for Technicolor filming, for example; but I even use it for exposing
chromogenic papers, as well as previously for Ilfochrome - that is, in distinction from ordinary subtractive YMC enlargement.

AgX
06-07-2013, 02:31 PM
Gaspar was the first to commercialize dye-destruction technique.

Furthermore he was inventive on several fields of colour photography.

Mustafa Umut Sarac
06-07-2013, 03:14 PM
If dyes being destroyed , what gives the colors ?

Thank you,
Umut

Mustafa Umut Sarac
06-07-2013, 03:16 PM
bleach removed the unwanted dyes.

I understood now , thank you . By the way, I researched carbon or dye transfer process and relief gives more freedom and pallette to grades. Is there such a relief at ilfochrome or similar trick ?

Umut

AgX
06-07-2013, 03:19 PM
The resting dye density
Think of the chromogenic dye technique where dyes are built up from zero density to their max. density depending on the image.
With the chromolytic (dye-destructive) technique it is just the other way round.

Mustafa Umut Sarac
06-07-2013, 03:33 PM
Thank you AgX , Is this paper manufacturable at home or are the dyes could be obtained and being ink jetted on to paper ?
Thank you Drew by the way .

Umut

AgX
06-07-2013, 03:40 PM
It is not the dyes alone. You need three halide layers including those dyes and get the silver-forming process coupled usefully to that dye-destruction.
I would not consider it more easy than making a chromogenic three-colour paper.

Mustafa Umut Sarac
06-07-2013, 03:45 PM
What is halide AgX ? Do dyes needed to be chemically treated to obtain the colors finally ?

AgX
06-07-2013, 04:01 PM
With halide I refered to silver-halide, AgBr etc.

In the presence of metallic silver, a low ph and a critical catalyst the dyes are bleached imagewise.

There had been papers that only employed dyes, being directly bleached during the exposure. I guess their inherent disadvantages are obvious.

Mustafa Umut Sarac
06-07-2013, 04:06 PM
So we need to create the colors of ilfochrome and we need to mix silver halide plus dye and plus catalyst and finally the color is ready.
It would be a very strong againts all conditions. Do this final color chemical soluble in water or alcohol ?

What is that catalyst ?

Thank you AgX.

Umut

AgX
06-07-2013, 04:15 PM
It would be proprietory. Though there have been postings here about synthezing a apt catalyst.

Mustafa Umut Sarac
06-07-2013, 04:37 PM
I found Rudefous post at articles , here it is .

The MSDS and many other descriptions I found online claim that 2,3,6-trimethyl-quinoxaline are used by Ilford. This substance, however, seems to be difficult to get, at least Sigma Aldrich doesn't seem to carry it. The Ciba patent mentions that very good results are obtained if a mix of two catalysts are used which have different redox potential, and based on that patent a combo of 2,3-dimethyl-quinoxaline and 2-hydroxy-3,6,7-trimethylquinoxaline could be very promising. I have, unfortunately not delved into this deeply enough, but the Ciba patent does mention patents which could provide useful recipes.

Mustafa Umut Sarac
06-07-2013, 04:49 PM
What else needed ?

Photo Engineer
06-07-2013, 06:32 PM
You need 3 coatable emulsions sensitive to R/G/B light. You need 3 Azo dyes such as Solantine Yellow, Solantine Pink and Chicago Blue. You need a developer such as Dektol, an acid dye bleach which is basically Sulfuric Acid mixed with a catalyst. One such is Phenazine. You need a fix that is a B&W fix.

There you go. Simple as can be. I've hand coated this mix and made some quite nice demonstrations of dye bleach.

But that was at EK. At home here, I did a single color Magenta, and posted the results elsewhere.

PE

Mustafa Umut Sarac
06-07-2013, 07:03 PM
Thank you , I remember now , I saw the red picture and it was an elegant color and strong , I dont know how to describe it technically .

Photo Engineer
06-07-2013, 07:06 PM
Good hue and saturation! :)

PE

falotico
06-08-2013, 03:25 PM
J.S. Friedman dedicates a whole chapter of "History of Color Photography" to Dr. Gaspar and his dye destruction process. The book is in English and is available for free online at http://archive.org/stream/historyofcolorph00frierich#page/n5/mode/2up and it is a wonderful source for information on many color photographic processes.

Dr. Bela Gaspar was one of the group of brilliant Hungarians who began remarkable careers in Hungary before WWII and then had to flee because of Nazi persecution. Gaspar himself wound up living in Beverly Hills, California and eventually his patents were licensed to several color film companies. He donated his papers to UCLA. Some of these patents were used to develop Cibachrome and Ilfochrome, which were both color processes depending on the destruction of dyes or dye precursors.

Gasparcolor was developed during the 1930's and some said that it produced better color than Technicolor. It had several advantages, but principally it allowed a laboratory which had only developed black and white films to develop full color films using ordinary black and white equipment and chemicals. This was unlike other color film processes and several Gasparcolor films were produced. Some of these movies are available on Youtube.

All of the color dyes were already incorporated in the Gasparcolor raw stock and the lab merely bleached out the color where it was not wanted. However the raw stock had to be exposed three times, one for each primary--red, green, blue--and Technicolor would not license their camera to Gaspar, so he did not have access to separation negs. An ingenious modification of a European movie camera was built which could produce alternating frames which recorded the scene in red, green and blue light successively; by filming at 72 frames per second and step-printing the three frames to a single full-color composite frame the camera could produce a full color movie that looked normal except for some fringing. I don't know of any examples of Gasparcolor films produced by this camera but I have seen a documentary of the current owners who showed the camera--it still exists--and described the rotating tri-color filter wheel in front of the lens.

Gasparcolor used commercially available dyes so the dye chemistry was reliable and stable. Without separation negs most examples of Gasparcolor films on Youtube are abstract films or animation, however there is one example of a Gasparcolor print of a Kodachrome(?) movie of a trip down the Thames River in London which has very good color tones. Dr. Gaspar licensed his process to a maker of stop-motion animated cartoons called "Puppetoons". Each frame had to be exposed three times, once through a red filter, once through a green filter and once through a blue filter. Moreover, the red exposure had to be for something like thirty seconds, the green for five and blue for one, (I'm guessing at the numbers).

I talked to a person who works for UCLA Film and Television Archives. He said that the Special Collections division of the UCLA libraries is difficult to work with, so it will be a problem to gain access to Dr. Gaspar's papers in their collection. If I do I will make a report to anyone who is interested online. I think Dr. Gaspar was a great chemist and he made an important contribution to color photography.

Photo Engineer
06-08-2013, 06:41 PM
While Gaspar may have used 3 exposures, it was not necessary to do so. The 3 exposures with different times were used to balance the film to the light.

And, one thing that is missed is that since the dyes are in the film from the start, the film is totally black and thus is very very slow, even with coarse grained emulsions.

Thus, from the very start, DB materials were slow, sharp but very very grainy.

PE