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Historical archives

I guess it would be interesting to reproduce here some of the tricks used by the earlier photographers. It is funny to notice that many technical issues we are facing today... were already existing in 1900.

Need one example ? Protect a photo against the counterfeiting.


Photographers in 1900 were artists but also chemists. At least, they had elementary knowledge how to handle dangerous products such as red Cyanid or sulphuric acid.

The hereunder chemical solutions are strictly given for historical purpose. I strongly invite you not trying to reproduce them. This is for your health !


Tinting photographies
When you try to touch up or to tint a photo, very often it is difficult to have the color being fixed on its surface.
In order to solve that problem, just move a potato newly cut onto the surface of the photography.
Then, the color will immediately stay
on the portions of the image this process has been applied.

Protect your photos against the counterfeiting

Partly soak the photo you want to protect in an aqueous solution of quinine sulfate. After drying, the
surface of the image will have no visible difference. After this process, if someone tries to take a photo of your image, the portions treated with the quinine sulfate will appear onto the fraudulent negative much darker than the other ones. Solutions of esculin or cinchonine bisulphate are giving similar results.

A diluted solution of fluorescein is the most efficient : just mop up the surface of your photo with a rubber pad dampened with the following solution :


Water ................  50 cc.


Fluorescein .......... 0, 3 gr


Glycerol ............. q.s.f 1000 cc.

Restoring ancien print
The print must be first, unstick from its back of cardboard. Then,  soak it during 10 minutes in the following solution :


Water ...................... 1000 cc


Bichloride of mercury .... 1,20 gr


Chloride of sodium .......  2,50 gr

Very quickly the image will almost completely disappear. To that point, wash the print with water and then soak it in a solution of diluted ammoniac.

The image will reappear very quicky with brown or black shade and a much better sharp.

Replace the frosted glass of a dark chamber
You can have a frosted glass of a much better quality that any other sold on the market. To do so, expose during few seconds a plate of gelatino-bromide to the light of a candle. Then, develop the plate until it has a dark shade and fix it. Wash it into water and then make lighter the layer in a solution of bichloride of mercury. Wash it again and then, dry it.

Retouch prints on glossy paper
Except if you apply a special treatment, it is difficult to retouch with water colors, a print made on glossy paper. To be able to do it easily, apply onto the image some drops of turpentine and let evaporate excess using a gentle heat.
In order to avoid the colors become dull when drying, add some drops of a solution of gum arabic or albumin into the water paint. To obtain a solution of albumin, drop a the white of an egg in a 100 cc flask and add 1 or 2 cc of liquid ammoniac. Fill up the flask with wate and shake it. 

Making of light filters for photo laboratory
Soak two old plates of gelatino-bromidedeux in a solution of hyposulfite at 20% added with a small quantity of red cyanid (This process is used to dissolve silver salt from the surface of the plates).
When this dissolution is achieved, carefully wash the two plates and proceed with their tinting.
Soak the first plate in a solution containing 3 gr of violet of methyl diluted with 1000 cc of water.
Soak the second plate in a solution of 6 gr of Tartrazin diluted with 1000 cc of water. Let the plates at least a quater of an hour in these coloring baths. Then gently wash them and let dry.

Then, stack the two plates, layer onto layer, and attach them together with a paper frame. You will obtain a filter which will retain all radiations of the solar spectrum except the red. You will use this filter in front of the beam of light when you have to operate in your photo laboratory.

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