Photoshop / White Balance
October 14, 2013 § Leave a comment
n this session with Steve we looked at how to correct the white balance of a photograph, giving the overall image a better look by adjust the tones of RGB colours.
The next step was to add the ‘Histogram’ panel from the ‘Window’ drop down, this panel will display a histogram giving you an overall idea about the colours used in an image (RGB) – the left of the scale indicates ‘darks’, ‘mixed lows’ in the middle, and ‘high lows’ on the right.
The ‘Adjustment layers’ panel, above the layers panel, displays a variety of filter like options, for this session we required the use of ‘Curves’, with this we can adjust the ‘exposure’ by sliding the bottom bar, by holding ‘Alt‘ you can actually see the exposure, sliding this until you are able to see the firs few pixels showing through.
The next step is to set up reference points in the image using the colour picker tool + holding ‘Shift’, for this you’d select 3 points (for this particular image of someone’s face anyway): 2 of them are placed on a lighter and darker skin tone, then the 3rd point is placed on a neutral colour I.e. white or grey (in this instant).
To view the values of the RGB press ‘Window’ and ‘Info’, the numbers located on the right show the brightness: neutral numbers of white are 255, and 0 for black,. The next to do is balance out the RGB values, this is done using the icon displaying a hand pointing it’s finger with arrows pointing up and down, with this tool selected click on both of the points (on the skin), this will put two new points on the histogram (for whatever colour you’re one), you then have to click in the middle of these two new points, then deleting them so you’re left with the center point, you’ll have to do this for each red, green and blue. Select this point on the histogram and move it with the up and down arrow keys, this is the general rule of thumb when balancing out these values (look at the right numbers on the info panel):
Look for about […] degrees of separation in RGB:25-30 degrees more green than blue40-60 degrees more red than green