I am looking for an explanation of what this command is doing, and by way of learning this, find out how to apply it within PSPx.

I have successfully followed the tutorial for extracting a sky from the tree limbs as described at:
http://photoshoptechniques.com/forum/showthread.php?t=16034

I had to use PS7 to accomplish this because I did not know how to get a multiply blend mode into a Mask in Paint Shop Pro, but more importantly, I did not know what the Filter/Other/Maximum command was doing.

Can someone who is knowledgeable in Photoshop tell me what this command is doing? Can anyone using Paint Shop Pro who is interested, tell me what steps I need to modify from the tutorial to make this work in PSPx?

I appreciate any advice and help.

Thanks,

Ken

Hi Ken,

Technically, the Maximum filter applies a choke spreading out white ares and choking black ones. Within a specified radius the Maximum replaces the current pixel brightness value with the highest value of the surrounding pixels.
This filter is typically used on masks to contract or expand the active area. For example if you have made a layer mask of a subject and pasted in a new background and you have a fine white or black fringe / halo around the subject which is being caused by the mask, you can just click on the mask and do a Maximum to expand or contract the masks active area by 1 or 2 pixels. There is no need to select anything.

A practical use of the Filter>Other>Maximum in Photoshop is equivalent to Select>Modify>Expand but here is the difference. Say you make selection with the lasso tool and you want to expand it a bit because it looks too small. You go Select>Modify>Expand. The question is how many pixels is correct? You don't have a preview window so you need to proceed on trial and error. Now try the following. Make the same selection. Next click on the Quick Mask button which you will find in your tool bar, 3rd from the bottom - it is just below the Foreground/Background color swatches, and it is the circle on your right. You will see the image masked in red except for your selection. Now go Filter>Other >Maximum and enter a pixel value. Voila, you can actually preview the result accurately. When you are done, just click the circle to the left of the Quick Mask button and you are back to Normal mode with your selection still active and modified. This method takes an extra couple of steps but can save you time in the end.
While we are on the Max filter it is worth noting that Filter>Other >Minimum ihas the opposite effect of Maximum it chokes white and expands black. An use of it is equivalent to Select>Modify>Contract. The technique is exactly the same using Quick Mask, but this time you will be shrinking the selection by some number of pixels.
Regards, Murray



Regards, Murray

Murray: thanks for the explanation on this, and for your reply about printer papers. I appreciate the help.

Ken