Line problems - DPChallenge Forums

Canon EF 24-70mm f/2.8L USM

03/12/2005 03:43:31 PM · #1

Ugh.. I am having some reduction problems with my line entry. As soon as I take the size down to 640 the lines that were all smooth and straight now look as if they are braided and knotted with dark and light alternating patches... the large file is fine, but the reduced one looks like crap. Anyone know what is taking place and a way to avoid braided/knotty looking lines when you reduce a photo?

gloda

Canon EOS-5D Mark II

03/12/2005 03:59:06 PM · #2

I think it depends on the resize matrix you use. PSP9 lets me chose between, for example, bicubic, pixel resize, smart resize...
Smart Resize brings the best results for me, I think it recognizes takes into consideration the edges.

itripn

Canon PowerShot G3

Canon EF 80-200mm f/4.5-5.6 II

03/12/2005 04:00:39 PM · #3

What application are you using to do the resize? Most applications allow you to chose the particular method of resizing. For instance, the GIMP gives a choice of 3, from fastest (lowest quality) to slowest (best quality).

However, if the lines in your photo are very fine, and more or less solid in color with lots of contrast between surrounding pixels, you're likely to be out of luck. Anti-aliasing might help, but I believe that would be considered a partial touch-up, and therefore illegal.

Good luck.
itripn

03/12/2005 04:11:09 PM · #4

Elements 2 is the application

03/12/2005 04:56:00 PM · #5

I'd be astonished if anti-aliasing were illegal.

Incidentally, downsizing in 10% increments will help a LOT with the problem you describe.

Robt.

Message edited by author 2005-03-12 16:56:45.

Canon EF 24-105mm f/4.0L IS

03/12/2005 05:34:19 PM · #6

Ah, thanks, I will try that.

Natator

Canon EOS-5D

03/12/2005 08:43:22 PM · #7

Originally posted by bear_music:

Incidentally, downsizing in 10% increments will help a LOT with the problem you describe.

Robt.

Not neccessarily.

In PS CS there are two new interpolation algorithyms for resizing images. Both are based on bicubic interpolation, but focus on keeping the image smoother or sharper - "Bicubic Smoother" and "Bicubic Sharper".

Typically Bicubic Smoother works better on images you need to enlarge and removed the need for intermediary interpolation and Bicubic Sharper where you need to downsize.

Basically, with these "tools" the old requirement for the 10% steps is no longer required. Some people do it out of habit, but at the end of the day you are not going to see any difference using the 10% steps over using this new method, in PS CS at least.

Now, that comes from a book I read, verious web sources, and originally came from Adobe (i think it is still on their web site somewhere).

I have seen others suggest that you should still use these new tools, but stick to the 10% steps, though I have only ever seen that stated on the web (i.e. take it or leave it).

Personally, I have yet to see an advantage with the 10% step method over the new method, but my eyes are not as good as mant.

Message edited by author 2005-03-12 20:47:42.

03/12/2005 08:55:56 PM · #8

That's as may be, but I'm still using 7.0 and I don't have that option. For me the incremental reduction works wonders.

Robt.

03/13/2005 07:51:53 PM · #9

Worked, thanks.

03/13/2005 08:25:29 PM · #10

Which worked?

Robt.

03/13/2005 08:27:07 PM · #11

The down by 10%... I have elements do no other options which I am aware of.