Method and apparatus for determining the time intensity integral of the exposure of a negative onto photographic paper

The method of forming a color print from a color negative by controlling the time intensity integral of the exposure comprising the steps of:

• a. scanning said negative by transmitting light sequentially through predetermined sampling areas of said negative;
• b. detecting the light transmitted through said negative in each of the colors, red, green and blue;
• c. generating an electric signal for each of the primary additive colors, linearly proportional to the fraction of the total area of the negative having a transmissivity greater than the mean transmissivity of the area;
• and
• d. setting the time intensity integral of the exposure in each of said colors proportional to the electric signal generated for that color.

The method of forming a color print from a color negative by controlling the time intensity integral of the exposure comprising the steps of:

• a. scanning said negative by transmitting light sequentially through predetermined sampling areas of said negative;
• b. detecting the light transmitted through said negative in each of the colors, red, green and blue;
• c. generating an electric analog voltage for each of the primary additive colors, linearly rotational to the fraction of the total area of the negative having a transmissivity greater than the mean transmissivity of the area;
• and
• d. setting the time intensity integral of the exposure in each of said colors proportional to the electric analog voltage generated for that color.

The method of forming a color print from a color negative by controlling the time intensity integral of the exposure comprising the steps of:

• a. scanning said negative by transmitting light sequentially through predetermined sampling area of said negative;
• d. detecting the light transmitted through said predetermined sampling areas of said negative in each of the primary additive colors, red, green and blue;
• c. generating a group of three analog voltages each corresponding linearly to a different one of said primary additive colors, each voltage proportional to the percentage of the total area of the negative having a transmissivity greater than the mean transmissivity of the whole area of the negative in that color;
• and
• d. controlling the exposure of said color negative onto said color print by setting the time intensity integral of the exposure in each of said colors proportional to the electric analog voltage generated for that color.

Apparatus for determining the time intensity integral of the exposure of a negative onto photographic paper comprising:

• a light source;
• means directing light from said light source through said negative through a plurality of predetermined discrete areas in said negative;
• a plurality of photodetecting means, each responsive to a different primary additive color, and each positioned to receive the light transmitted through said negative for generating electric signals linearly proportional to the intensity of light incident thereupon;
• a plurality of electric circuit means, each connected to a different one of said photodetecting means, and each responsive to the electric signals generated by a photodetecting means connected thereto for generating an analog voltage proportional to the fraction of the total number of said discrete areas having light transmission higher than the mean light transmission of all of said areas;
• and timing means connected to said electric circuit means responsive to the amplitude of each of said analog voltages for terminating the exposures of said negative in the color corresponding to each of said analog voltages in accordance with said amplitude.

Apparatus for determining the time intensity integral of the exposure of a negative onto photographic paper comprising:

• a light source;
• means directing light from said light source through said negative through a plurality of predetermined discrete areas in said negative;
• a plurality of photodetecting means, each responsive to a different primary additive color, and each positioned to receive the light transmitted through said negative for generating electric signals linearly proportional to the intensity of light incident thereupon;
• a plurality of electric circuit means, each connected to a different one of said photodetecting means, and each responsive to the electric signals generated by a photodetecting means connected thereto for generating an analog voltage proportional to the fraction of the total number of said discrete areas having light transmission higher than the mean light transmission of all of said areas;
• and means connected to said electric circuit responsive to the amplitude of each of said amplitude voltages for presenting an indication of the amplitude of each of said analog voltages.

The method of forming a color print from a color negative by controlling the time intensity integral of the exposure comprising the steps of:

• a. scanning said negative by transmitting light through it and detecting said light separately for a plurality of individual illuminated areas of said negative;
• b. generating an electric signal for each of the primary additive colors, linearly proportional to the fraction of the total area of the negative having a transmissivity greater than the mean transmissivity of the area;
• and
• c. setting the time intensity integral of the exposure in each of said colors proportional to the electric signal generated for that color.

Apparatus for generating an analog voltage in response to light transmitted through a negative comprising:

• a. a light source;
• b. means for scanning said negative at a plurality of discrete areas;
• c. a plurality of photodetecting means each responsive to a different additive primary color and each positioned to receive the light transmitted through said discrete areas for generating electric signals linearly proportional to the intensity of the light in an additive primary color incident thereupon;
• d. a plurality of circuit means each connected to a different one of said photodetectors for receiving one of said electric signals, each of said circuit means including:
• 1. dividing means for receiving and dividing said electric signal into first and second signals;
• 2. integrating means connected to said dividing means for receiving and integrating said first signal;
• 3. a voltage comparator connected to said dividing means and to said integrating means for receiving said second signal and the integrated first signal and for generating a train square wave pulses of predetermined amplitude having a duty cycle proportional to the time that said second signal is higher than said integrated first signal;
• and
• 4. second integrating means connected to said comparator for receiving and integrating said train of square wave pulses to form an analog voltage linearly proportional to the fraction of the total area of said negative having light transmissivity higher than the mean transmissivity of said total area.