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Old 03-01-2005, 06:07 PM   #1
Garth Herrick Garth Herrick is offline
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Removing Keystoning and Perspective Distortions in Photoshop




Since I often photograph my paintings at an angle to avoid glare, I need to digitally straighten them out again, using Photoshop. Here's how:

Removing keystoning from a photographed rectangular work is not difficult in Photoshop. Use the Crop tool to get within a quarter inch of your painting, (but not too close). With the NAVIGATOR, ZOOM IN to at least 100%, or much more. Now SELECT/SELECT ALL. Go to EDIT/TRANSFORM/DISTORT. You will find in the corners, 4 small box buttons. Drag each of these out one at a time until you get each corner of your painting pulled tight to the corners of the image file frame. Press ENTER or RETURN (Mac), to accept these changes. Any perspective distortion present in the original image will be corrected now.

To get the proportions or aspect ratio of your painting back on track, take measurements of your original painting, go to IMAGE/IMAGE SIZE, disable the CONSTRAIN PROPORTIONS checkbox, so you can alter them. Now type into the height and width dimension boxes, the actual measurements of your painting. Since this may increase your file size to something overwhelming, you can reduce the pixels per inch to something much smaller than 300dpi to something like 96 dpi, or 72 dpi. Press OK, and your painting will be flat, square, true proportioned, and looking good! Remember to go back and reset the CONSTRAIN PROPORTIONS checkbox in IMAGE SIZE, for the next time you use that function, especially if you wish to resize your painting to post onto the Forum.

I hope this is helpful,

Garth
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Old 03-02-2005, 12:11 AM   #2
Elizabeth Schott Elizabeth Schott is offline
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Bravo Garth, I promise you a "path" discussion as soon as I have time!
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Old 07-21-2005, 03:48 AM   #3
Carolyn Ortiz Carolyn Ortiz is offline
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Thank you Garth!

I've been having a really awful time with camera distortion lately. I just tried this in PS and it worked GREAT!!!

Thank you! Thank you!

~Carolyn
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Old 07-21-2005, 11:21 AM   #4
Geary Wootten Geary Wootten is offline
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thumbs up Yay!

Tres Cool Garth! You just saved me a ton o' grief with a project I'm working on that has to be perfected in a manner that can be repeated correctly (mathematically) everytime.

Thanks!

~Gear
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Old 07-25-2005, 04:13 PM   #5
William Whitaker William Whitaker is offline
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Garth,

I followed your instructions and I've already corrected a number of old images.

I did this drawing of Dan George in 1975, back when I was in too big a hurry to take a careful shot. Here is the cropped original.
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Old 07-25-2005, 04:15 PM   #6
William Whitaker William Whitaker is offline
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Here it is after following your instructions.

Thanks so very much. I now have the tool to correct a lot of old distorted shots.

Bill
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Old 07-25-2005, 04:37 PM   #7
Mike McCarty Mike McCarty is offline
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Great drawing Bill.

I love this guy, Chief Dan George. You must have done this about the time of "The Outlaw Josey Wales," when he said: "We shall endeavor to persevere."

He was 60 when he became a movie actor and 71 when he was nominated for an academy award in "Little Big Man," with Dustin Hoffman. He gives hope to us old timers.
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Old 08-12-2005, 12:39 PM   #8
Lisa Ober Lisa Ober is offline
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Awesome advice. I had the right idea but didn't think of measuring the original to get the proportions right. I wish I would have read this last night when I practically took photos in the dark to avoid glare.

Thank you so much!
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Old 08-21-2005, 01:24 AM   #9
Tricia Migdoll Tricia Migdoll is offline
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Thanks Garth,

I just tried this and it works beaut.
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Old 08-21-2005, 10:23 PM   #10
Marcus Lim Marcus Lim is offline
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Hi Garth, this is a neat trick! And it couldn't have come to us at a better time! I was tired of struggling through getting the right adjustments, until your handy tip came along!
Thanks mate!
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