2. How to eliminate vignetting

Translation by Christoph Jansen

Before After
M33 photography copyright 2002 by Andy Bender, taken with Celestron 11'' SC, Giant Easy Guider. Thank you!

Step 1:

Choose the irritating color in the vignetted area using the eye dropper tool. In the course of the following steps you will probably have to try this several times until you find out the correct color. It's a little tricky!

Step 2:

Create a new layer using the character combination CTRL+SHIFT+N (menu "Layer"->"New Layer") and click into this Level with the paint bucket. The layer is then filled with the color chosen in step 1. The original picture seems to vanish, but it still exists in the background layer, so don't panic.

Step 3:

Invert the layer's color after filling using the combination CTRL+I.

Step 4:

Set layer mode to "Color Burn". If you can't see the Layer-Window, you have to pop it up using the "Show Layers" option in the "Window" menu. Now combine the two layers (background and layer 1) to a new background with CTRL+E (Flatten Image). To check the picture's appearance with or without the new layer, you can switch the layer on/off using the eye symbol in the layers window (the symbol just crossed by the red circle in the example below).

Step 5:

Call CTRL+L to adjust the histogram and slowly move the rightmost small triangle to the left until the pictures' brightness seems acceptable (to simultaneously observe the progress activate the "Preview" option; see checkbox at the lower right of the dialogue).

Step 6:

These steps may be repeated several times using different colors (depending on the brightening of the vignetted area) until you find the result acceptable. You may now save the picture UNDER A NEW NAME.
Please, don't ever overwrite the original, you're sure to be sorry for losing it!!!

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