Photoshop damaging images when rotated??

Art Couch wrote:

I remember reading about this potential problem a few weeks ago and

ran into

it myself tonight. I’m not sure how many rotations it is taking, but

I

definitely notice jagged edges after rotating and zooming the image

to 300%.

Have you checked your default interpolation method preference? If it’s "nearest neighbour", I would expect plenty of degradation… –Toby

I had a print turn out bad a couple of weeks ago and thought it was

the

printer/ paper. The print had the same jagged edges. Now there’s no

doubt

where this is coming from. Good thing I saved the original image and

not

the rotated one! The question is: what’s causing it? I am just

doing

standard rotations by inputting the angle to be rotated and I haven’t touched the transform commands at all. I am using PS CS.
Thanks,
Art

There is a rounding error in Photoshop. From what I understand it has been there for a very long time. The bad part is you get image degradation. The fun part is you do it enough it creates a very interesting effect.

To see what I mean go here: http://www.russellbrown.com/tips_tech.html

Download the Shake, Rattle and Roll script and try it on an image. Its really neat.

John

"Art Couch" wrote in message

I remember reading about this potential problem a few weeks ago and ran into
it myself tonight. I’m not sure how many rotations it is taking, but I definitely notice jagged edges after rotating and zooming the image to 300%.
I had a print turn out bad a couple of weeks ago and thought it was the printer/ paper. The print had the same jagged edges. Now there’s no doubt
where this is coming from. Good thing I saved the original image and not the rotated one! The question is: what’s causing it? I am just doing standard rotations by inputting the angle to be rotated and I haven’t touched the transform commands at all. I am using PS CS.
Thanks,
Art

"toby" wrote in message

Art Couch wrote:

I remember reading about this potential problem a few weeks ago and

ran into

it myself tonight. I’m not sure how many rotations it is taking, but

I

definitely notice jagged edges after rotating and zooming the image

to 300%.

Have you checked your default interpolation method preference? If it’s "nearest neighbour", I would expect plenty of degradation…

The default is bicubic. That’s what I always use for enlarging or rotating.

Art

–Toby

I had a print turn out bad a couple of weeks ago and thought it was

the

printer/ paper. The print had the same jagged edges. Now there’s no

doubt

where this is coming from. Good thing I saved the original image and

not

the rotated one! The question is: what’s causing it? I am just

doing

standard rotations by inputting the angle to be rotated and I haven’t touched the transform commands at all. I am using PS CS.
Thanks,
Art

"John Doe" wrote in message

There is a rounding error in Photoshop. From what I understand it has been there for a very long time.

I wish I had known about this error before. It would have saved me a lot of extra work to go back and blur out the jagged edges, and thus compromising the picture sharpness. I do a LOT of rotating so I may have to find another alternative program if I’m going to end up with artifacts like these! I’m surprised for the amount of $ this program costs that they’d allow an error like this. Maybe there is a fix or patch?? I hope so and if someone could shed some light, I’d appreciate it. If not, I need to find another program for my rotations!

The bad part is you get image degradation. The

fun part is you do it enough it creates a very interesting effect.

It might be an interesting effect, but not good when you’re trying to process professional prints!

Art

To see what I mean go here: http://www.russellbrown.com/tips_tech.html
Download the Shake, Rattle and Roll script and try it on an image. Its really neat.

John

"Art Couch" wrote in message

I remember reading about this potential problem a few weeks ago and ran into
it myself tonight. I’m not sure how many rotations it is taking, but I definitely notice jagged edges after rotating and zooming the image to 300%.
I had a print turn out bad a couple of weeks ago and thought it was the printer/ paper. The print had the same jagged edges. Now there’s no doubt
where this is coming from. Good thing I saved the original image and

not

the rotated one! The question is: what’s causing it? I am just doing standard rotations by inputting the angle to be rotated and I haven’t touched the transform commands at all. I am using PS CS.
Thanks,
Art

Not to question the validity of your problems, but don’t you get max screen rez only at 25, 50, 100, 200, 400% etc? Could this have something to do with the jaggies at 300%?

KB

"Art Couch" wrote in message

I remember reading about this potential problem a few weeks ago and ran into
it myself tonight. I’m not sure how many rotations it is taking, but I definitely notice jagged edges after rotating and zooming the image to 300%.
I had a print turn out bad a couple of weeks ago and thought it was the printer/ paper. The print had the same jagged edges. Now there’s no doubt
where this is coming from. Good thing I saved the original image and not the rotated one! The question is: what’s causing it? I am just doing standard rotations by inputting the angle to be rotated and I haven’t touched the transform commands at all. I am using PS CS.
Thanks,
Art

"Ken Burns" wrote in message

Not to question the validity of your problems, but don’t you get max

screen

rez only at 25, 50, 100, 200, 400% etc? Could this have something to do with the jaggies at 300%?

KB

That has nothing to do with it because I see the artifacts on rotated printed images.

Art

"Art Couch" wrote in message

I remember reading about this potential problem a few weeks ago and ran into
it myself tonight. I’m not sure how many rotations it is taking, but I definitely notice jagged edges after rotating and zooming the image to 300%.
I had a print turn out bad a couple of weeks ago and thought it was the printer/ paper. The print had the same jagged edges. Now there’s no doubt
where this is coming from. Good thing I saved the original image and

not

the rotated one! The question is: what’s causing it? I am just doing standard rotations by inputting the angle to be rotated and I haven’t touched the transform commands at all. I am using PS CS.
Thanks,
Art

I didn’t know if it had anything to do with it or not. That’s why I asked the question.

KB

"Art Couch" wrote in message

"Ken Burns" wrote in message

Not to question the validity of your problems, but don’t you get max

screen

rez only at 25, 50, 100, 200, 400% etc? Could this have something to do with the jaggies at 300%?

KB

That has nothing to do with it because I see the artifacts on rotated printed images.

Art

"Art Couch" wrote in message

I remember reading about this potential problem a few weeks ago and ran into
it myself tonight. I’m not sure how many rotations it is taking, but I definitely notice jagged edges after rotating and zooming the image to 300%.
I had a print turn out bad a couple of weeks ago and thought it was the printer/ paper. The print had the same jagged edges. Now there’s no doubt
where this is coming from. Good thing I saved the original image and

not

the rotated one! The question is: what’s causing it? I am just doing standard rotations by inputting the angle to be rotated and I haven’t touched the transform commands at all. I am using PS CS.
Thanks,
Art

"Art Couch" wrote in message

"John Doe" wrote in message

There is a rounding error in Photoshop. From what I understand it has

been

there for a very long time.

I wish I had known about this error before. It would have saved me a lot

of

extra work to go back and blur out the jagged edges, and thus compromising the picture sharpness. I do a LOT of rotating so I may have to find

another

alternative program if I’m going to end up with artifacts like these! I’m surprised for the amount of $ this program costs that they’d allow an

error

like this. Maybe there is a fix or patch?? I hope so and if someone

could

shed some light, I’d appreciate it. If not, I need to find another

program

for my rotations!

Rotation will always degrade an image to some degree, because you’re resampling; there’s no perfect 1:1 mapping of pixels for angles other than steps of 90 degrees,

Ian

Depends on the type of rotation. If you are simply doing 90, 180 and 270° rotations, try IrfanView. It will even to a loseless jpg rotation for you. If you are doing random amount rotations, look at Paint Shop Pro as an alternative. It also has some automation for fixing photos that is better, in my view, than Photoshop, so I use both programs – each for what it is best for… Using the stamp feature in Photoshop and the fixing features in PSP for many images.

FWIW

RsH
——————————————————— On Thu, 10 Feb 2005 19:29:30 GMT, "Art Couch" wrote:

Maybe there is a fix or patch?? I hope so and if someone could shed some light, I’d appreciate it. If not, I need to find another program for my rotations!

You can rotate 2 or 3 times without much trouble, but beyond that and you will start seeing the problems. I don’t know why anyone would need to rotate a single image more than once or twice?

John