Curves
Clive R. Haynes FRPS
Let's make other, very straightforward, alterations to the shape of the 'Curve' and the logic will become more apparent.
What happens if, instead of altering bending the shape of the curve we
move it along the edges of the gradients?
Let's explore these options.
Above:
Let's examine what's happening in the dialogue box above.
The pale grey diagonal line indicates the starting point for the curve
- we can refer to this as the 'normal position'. Any distortion or movement
from 'normal' will affect the image in some way. It's a good idea to always
bear in mind the slope of the line from corner to corner when beginning
to make changes, as alterations to the shape of the curve can then be
related to the starting point. In other word we can picture just how far
from the straight line we have strayed.
In the example above
we can see that the light grey area on the lower gradient scale, representing
('Input') 'light', has been pushed over to the left along the top edge.
This instructs the ('Output') 'ink' to print all tones to the right of
the chosen grey area as white. Light greys become white.
This 'movement' has the additional effect of taking the whole straight
line of the 'Curve' towards the left and this also lightens the image.
The dark greys remain little affected and the black point remains anchored
at the corner, black = black.
This 'movement' has the additional effect of taking the whole straight line of the 'Curve' towards the right and this also darkens the image. The light greys remain little affected and the white point remains anchored at the corner, white = white.