Chromogenic

Overview Object View Surface View Magnification Variations

Chromogenic Surface View

Surface Sheen 
Surface sheen can vary depending on the support and structure of the print and post processing techniques, such as ferrotyping. Fiber-based prints are usually glossy due to ferrotyping. Prints on acetate and polyester supports have a high gloss surface sheen. Kodachrome prints exhibit differential gloss. Smooth resin coated prints typically have a glossy surface. Resin coated papers with an applied texture can have a semi-matte, semi-gloss, or glossy surface sheen. 
Kodachrome prints like Kodachrome slides exhibit differential gloss.

Kodachrome prints like Kodachrome slides exhibit differential gloss.

Fiber-based prints are typically glossy as seen in the image on the left. Fiber-based prints could be ferrotyped to enhance the surface sheen.

Fiber-based prints are typically glossy as seen in the image on the left. Fiber-based prints could be ferrotyped to enhance the surface sheen.

Kodak RC consumer grade papers came in four surfaces, smooth glossy (F) and three textures (E, N, Y) resulting in a range of surface sheens.

Kodak RC consumer grade papers came in four surfaces, smooth glossy (F) and three textures (E, N, Y) resulting in a range of surface sheens.

Commercial papers made by Kodak and other manufacturers came with a range of textures and sheens.

Commercial papers made by Kodak and other manufacturers came with a range of textures and sheens.

Surface Texture 
Surface can texture can vary. Fiber-based prints have a thick, smooth baryta and therefore a smooth surface. Resin coated papers were introduced in 1968 with three different surface textures, a smooth surface and two distinct surfaces (Kodak silk also called Y and Kodak N). In 1976 another surface texture was introduced (Kodak E). To create the textures, pigmented polyethylene was extruded onto the paper support, passed through a nip and was cooled against a textured steel roller called a “chill roll.” Prints with cellulose acetate and polyester supports have a smooth surface. 
Fiber-based prints have a smooth texture.

Fiber-based prints have a smooth texture.

Kodak resin coated consumer papers had four surfaces. The “F” was smooth and “E” “N” and “Y” papers had applied textures. “N” has a very slight texture while “E” and “Y” have more distinctive textures.

Kodak resin coated consumer papers had four surfaces. The “F” was smooth and “E” “N” and “Y” papers had applied textures. “N” has a very slight texture while “E” and “Y” have more distinctive textures.

Other applied textures were also available for commercial papers.

Other applied textures were also available for commercial papers.

Fluorescence
Photographic paper manufacturers began adding optical brightening agents (OBAs) to materials beginning the in the mid-1950s. Use of OBAs increased rapidly throughout 1960s becoming relatively prevalent in the in the 1970’s with the use of RC papers. OBAs are special dyes that absorb ultra violet radiation and emit a bluish-white light. The purpose of OBs is to make whites appear whiter and counteract yellowness. They were added to the paper support, baryta, and/or emulsion or added to the processing chemicals. Gelatin and baryta have a natural fluorescence making small amounts of OBAs difficult to detect.
OBAs fluoresce under UV light. They counteract yellow discoloration.

OBAs fluoresce under UV light. They counteract yellow discoloration.