Darkroom: Standard Light

NOTE: the lightbulb shown above is the light I use for making contact Azo prints. It is not an enlarger lamp. 

A standard light is the the guidance setup, or initial configuration of an exposure recommendation to match one source to another.

enlarger

Standard Light

The standard light setup will be used in making masks, and separations, in addition to other darkroom procedures such as characterizing paper and developer. In my practice  I no longer start with the guidance of the manufacturers since I’ve characterized so many films/papers for so many years I just start with my own best last information. That is usually written on tape at the enlarger, or has been set into the darkroom meters I use.

Ilford EM-10

Ilford no longer makes the EM-10. In the 90s it sold for $28. Mine still works just fine, even though I rarely use it. I have much more sensitive and accurate digital meters. Ilford provides the calibration instructions at: EM-10

Ilford Meter
EM-10

//TBD w ref link to Darkroom Tronics

280082C
300082A — note: original lit (1950s) relied upon PH211, hence no filter usedPH211 & 212
3200STANDARD CT .. NO FILTER NEEDED. dichroic standard
330081EVW
340081A decreases color temperature 200 KelvinELB & PH213
Color Temperature and Conversion

Side Note: Tricolor Printing Filters

wavelengths of RGB that most color photographic papers respond to best are the wavelengths that are passed by Kodak Wratten filters

Tricolor Separation Printing

The original color printers, as well as the recommended printing method for Type “C” papers, used the additive filters. Three exposures were made using WR98,WR99 and WR70 (alternatively 29) filters. Kodak and Fuji have since improved color separation between the Type C (RA4) color layers. Additive printing was essential to take out the ‘pumpkin’ yellows. The tricolor method kept the yellows clearer.

use the WR70 as the base exposure. The Red layer of the paper is the speed determining layer.
  • The Reproduction of Color, Hunt 5th Ed. p.177-192.
  • The Color Gamut Obtainable by the Combination of Subtractive Color Dyes. Optimum Absorption Bands as Defined by NonlinearOptimizationTechnique, J.ImagingScience, 30,9–12; by N. Ohta.
  • Brightness and Hue of Present Day Dyes in Relation to Colour Photography, by ME Clarkson and T. Vickerstaf, PhotoJ.88b,26(1948).