Apply a sharpen filter to enhance images. There are 8 enhancement levels available (0, 12%, 25% .... 87%, 100%). Choose the sharpen (enhancement) tool for either one of the mouse buttons, click on the image and move the mouse right to increase the enhancement level or left to decrease. Enhancement filters increase the noise of an image.
See images below, left the original image and right enhanced image with the enhancement tool assigned to the left mouse button.
An other way to apply the enhancement filter is via the menu. Go to 'Tools' and 'Sharpen' to choose a level.
Left angiogram, no filter. Right angiogram, a 75% enhancement filter is applied using the sharpen tool with the left mouse button