The human eye perceives color, focusing on the intensity of three components: red, green and blue. This uses receptors called cones. They are significantly less sensitive than monochromatic receptors called rods.
Instructions
Step 1
Take a photocell with a red photoeffect border no shorter than 800 nanometers. Its sensitivity curve should be linear. Connect the element to the measuring device, taking into account its design features. They determine, in particular, the required sensitivity of the device, the presence or absence of the need to use a power source, compliance with polarity, etc.
Step 2
Aim the photocell at a sheet of white paper. Direct a light source with a color temperature of about 4000 Kelvin at it. It is important to ensure that light from the source does not directly enter the element. Without changing the distance from the source and the element to the sheet, cover the latter in turn with red, green and blue light filters. Record the meter reading in all three cases. Take them as one hundred percent intensity for each of the primary colors.
Step 3
Without changing the position of the light source and photocell, instead of a white sheet at the same distance from them, place an object whose color you want to quantify. Cover the cell again with red, green, and blue filters in turn, recording the meter reading each time.
Step 4
To express the intensity of each of the three color components as a percentage, make a proportion: multiply the measurement of the intensity of this color when reflected from an object by 100, and then divide by the result of measuring the intensity of the same color when reflected from a white sheet.
Step 5
In HTML, color is represented by a string of six characters, the first two of which symbolize the intensity of the red component, the middle two - green, and the last two - blue. Each pair of characters is a hexadecimal number from 0 to FF. To express the color quantitatively in HTML, first make three calculations in the way indicated above, replacing in all cases the number 100 by 255. Then convert all three results from the decimal system to hexadecimal, and then write the translation results together, adding insignificant zeros if necessary. to make the numbers double-digit. For example, if the numbers are 0, 255, 8, then after transferring to the hexadecimal system and adding insignificant zeros, they will be written as 00, FF, 08, and in the HTML language the color will be called 00FF08.
