New life of old idea
Posted: Sat Nov 29, 2008 4:43 pm
I wish to break silence. Give let us recall very old and well the forgotten method of a color photography. It is a question about autochrome photo process which has invented by Alpheus Hyatt Verril in 1902. The essence of the method consists that on positive black-and-white emulsion the mask from the painted grains of starch which acted as filters is put
http:// home.bway.net/jscruggs/auto.html.
Let's apply this method to Lippmann’s photography, i.e. we shall arrange the mosaic RGB-filter between a substrate and emulsion (Pic.1). The greatest difficulties for the Lippmann’s method are represented with transfer low saturation colors close to white. It is connected with small coherent length of broadband color signals. The information on color tone is stored in the form of autocorrelation function and concentrated near to a surface of a layer. The slightest defects on a surface or shifting, lead to greater distortions in a colors rendition. Application of filters essentially increases quantity isophase planes and the information on color is distributed on all thickness of the layer. But it is necessary to pay for this advantage reduction of resolution of the obtained image.
The best place for the filter is a sublayer. On thin, well hardened the layer it is possible by means of the jet printer (or a different way, for example, silk-screen printings) to put the mosaic RGB-filter. And then put emulsion. It is possible also on a transparent film to print the mosaic filter, to paste it to a substrate and put emulsion.
Considering, that Lippmann’s emulsion has much greater thickness, than photographic, applied in autochrome process, it is possible to try some grain of starch (and it is better, any painted polymer, with a refraction index equal to RI gelatin) to arrange directly in the emulsion layer (Pic.2). For the beginning it is possible to try a powder for the color copier.
It is necessary to notice, that contrast interference pictures increases in any case, is not dependent on where there is a grain-filter. In places of overlapping of two filters the complementary color is recording, that also promotes accuracy of transfer of complex light tones.
Thus, association of two ancient ways with use of modern technologies can give unexpectedly good result.
All told above is fair and for color holography. I have considered this opportunity and have described in a Russian-speaking part of a forum few days ago.
http:// home.bway.net/jscruggs/auto.html.
Let's apply this method to Lippmann’s photography, i.e. we shall arrange the mosaic RGB-filter between a substrate and emulsion (Pic.1). The greatest difficulties for the Lippmann’s method are represented with transfer low saturation colors close to white. It is connected with small coherent length of broadband color signals. The information on color tone is stored in the form of autocorrelation function and concentrated near to a surface of a layer. The slightest defects on a surface or shifting, lead to greater distortions in a colors rendition. Application of filters essentially increases quantity isophase planes and the information on color is distributed on all thickness of the layer. But it is necessary to pay for this advantage reduction of resolution of the obtained image.
The best place for the filter is a sublayer. On thin, well hardened the layer it is possible by means of the jet printer (or a different way, for example, silk-screen printings) to put the mosaic RGB-filter. And then put emulsion. It is possible also on a transparent film to print the mosaic filter, to paste it to a substrate and put emulsion.
Considering, that Lippmann’s emulsion has much greater thickness, than photographic, applied in autochrome process, it is possible to try some grain of starch (and it is better, any painted polymer, with a refraction index equal to RI gelatin) to arrange directly in the emulsion layer (Pic.2). For the beginning it is possible to try a powder for the color copier.
It is necessary to notice, that contrast interference pictures increases in any case, is not dependent on where there is a grain-filter. In places of overlapping of two filters the complementary color is recording, that also promotes accuracy of transfer of complex light tones.
Thus, association of two ancient ways with use of modern technologies can give unexpectedly good result.
All told above is fair and for color holography. I have considered this opportunity and have described in a Russian-speaking part of a forum few days ago.