Home · Register · Join Upload & Sell

Moderated by: Fred Miranda
Username  

  New fredmiranda.com Mobile Site
  New Feature: SMS Notification alert
  New Feature: Buy & Sell Watchlist
  

FM Forums | Post-processing & Printing | Join Upload & Sell

  

Archive 2015 · Questions about Downsizing JPG files for screen and web viewing.

  
 
George Komiotis
Offline
• •
Upload & Sell: Off
p.1 #1 · p.1 #1 · Questions about Downsizing JPG files for screen and web viewing.


Hello all,

To avoid any confusion, my question is about downscaling digital files, not upscaling.

I believe we all agree that one can never beat the quality of the image at its native resolution, but as screen resolutions are most of the time lower than the native resolution of today's digital cameras, I need to optimize the way I downsize my photos for screen and web viewing with the minimum possible effect on image quality. So here come my questions:

1. When setting up the camera, is it better to start by choosing a smaller file size that will need less downsizing compared to a bigger file?
Does this affect/limit the ability of the sensor to give a high quality image or is it irrelevant since we'll end with a smaller file?

2. In Photoshop CS5, is it necessary or better to do the downsizing by steps of 5% until we get to the target size or it only applied to older versions of the software?

3. Is the use of dedicated resizing software a good option? If you believe so and even better if you use one, what software would you suggest?

Any input from technically advanced forum fellows about this topic would be much appreciated.



May 29, 2015 at 10:51 AM
Mnd1
Offline
• •
Upload & Sell: Off
p.1 #2 · p.1 #2 · Questions about Downsizing JPG files for screen and web viewing.


We've just been discussing this here.

https://www.fredmiranda.com/forum/topic/1367027



May 29, 2015 at 02:03 PM
Peter Figen
Online
• • • • •
Upload & Sell: On
p.1 #3 · p.1 #3 · Questions about Downsizing JPG files for screen and web viewing.


It's almost always better to start with the native resolution of your camera, if for no other reason, to not limit yourself for future output requirements. Ps CS 5 is fine for downsizing, although somewhat limited in interpolation options. Bicubic standard is usually the best choice as Bicubic Sharper, which is what Adobe recommends for downsizing, applies global sharpening, which often leaves high contrast transitions with visible halos. Iridient Developer does have several other interpolation choices, which may or may not improve your output depending on image content and final file dimensions.

The bottom line is that you're almost always going to have to make downsized files for web output. You want to choose the best interpolation routine for your image by trial and error and then carefully apply sharpening - usually Unsharp Masking, but maybe Smart Sharpen instead - where you have control over amount, radius and threshold, and apply that sharpening to a duplicate layer which can then be masked if need be. If you apply USM on duplicate layers you can also affect the light and dark halos separately simply by changing layer blend modes. Smart Sharpen has that feature built into the advanced portion of the filter already. You can also use the layer Blend If sliders to automatically mask portions of your image from filtering.

As far as never beating the quality of the original, I'm not sure I agree with that. The real answer is that it depends. Often, lower res versions of the file actually look better and smoother than the high res original, particularly in ultra high iso images where digital noise is a factor.



May 29, 2015 at 02:58 PM
Mirek Elsner
Offline
• • •
Upload & Sell: Off
p.1 #4 · p.1 #4 · Questions about Downsizing JPG files for screen and web viewing.


Photogeo180 wrote:
1. When setting up the camera, is it better to start by choosing a smaller file size that will need less downsizing compared to a bigger file?
Does this affect/limit the ability of the sensor to give a high quality image or is it irrelevant since we'll end with a smaller file?

It is best to start with the highest quality and amount of information in the file. My recommendation would be to shoot raw, which also means capturing in full resolution. If you must shoot jpeg, starting with maximum size will give you more flexibility going forward. In that case you should use the highest quality settings for your jpeg files and do final sharpening after downsizing.


2. In Photoshop CS5, is it necessary or better to do the downsizing by steps of 5% until we get to the target size or it only applied to older versions of the software?

I am not sure about the source (possibly Real World Image Sharpening, Fraser, Schewe), but experienced people who did some testing believe that this method is not useful in latest versions of PS anymore. I can't provide my own experience here, because my results with this method were always suboptimal.


3. Is the use of dedicated resizing software a good option? If you believe so and even better if you use one, what software would you suggest?


I personally do not rave about PS downsizing capabilities and tend to use software that uses Lanczos algorithm. It seems to provide a bit more natural looking details. Hosting the images on sites like Flickr is another option. You upload at full size and their downsizing will do decent work on resizing and also supports Retina displays.



May 29, 2015 at 05:26 PM
gdanmitchell
Offline
• • • • • • •
Upload & Sell: Off
p.1 #5 · p.1 #5 · Questions about Downsizing JPG files for screen and web viewing.


Photogeo180 wrote:
1. When setting up the camera, is it better to start by choosing a smaller file size that will need less downsizing compared to a bigger file?


No. There is no IQ advantage in doing that. The only possible advantages that I can think of might be if you are utterly certain that you will never, ever want a version of the image at its highest potential resolution and you want to save a little storage space (hardly worth it at today's low prices) or transfer files a little bit faster.

So, really, no.

Does this affect/limit the ability of the sensor to give a high quality image or is it irrelevant since we'll end with a smaller file?

You are interpolating pixels whether you do it in camera or in software. In software you have more control.

2. In Photoshop CS5, is it necessary or better to do the downsizing by steps of 5% until we get to the target size or it only applied to older versions of the software?

Don't bother doing that. Way back in the dark ages of digital photography some people felt that there was some advantage in upsizing images in this way — or using this approach for sharpening — when the change was a very large one.

Don't do it.

3. Is the use of dedicated resizing software a good option? If you believe so and even better if you use one, what software would you suggest?

Just use what's in Photoshop or Lightroom.

Any input from technically advanced forum fellows about this topic would be much appreciated.

I'm a "technically advanced" user.


Edited on May 29, 2015 at 09:20 PM · View previous versions



May 29, 2015 at 05:36 PM
colinm
Offline
• • • •
Upload & Sell: Off
p.1 #6 · p.1 #6 · Questions about Downsizing JPG files for screen and web viewing.


Mirek Elsner wrote:
I am not sure about the source (possibly Real World Image Sharpening, Fraser, Schewe), but experienced people who did some testing believe that this method is not useful in latest versions of PS anymore.


Indeed 'twas the late Bruce Fraser (and, from memory, in a column even prior to Real World Image Sharpening). Jeff Schewe's been carrying the torch since.

It's been ages since there was tangible benefit to stairstep interpolation. It's one of those things that refuses to die despite all forward progress, like (lest I restart a holy war) wamut gorning.




May 29, 2015 at 06:01 PM
George Komiotis
Offline
• •
Upload & Sell: Off
p.1 #7 · p.1 #7 · Questions about Downsizing JPG files for screen and web viewing.


Thank you all for the fast response and valuable input.
Things are much clearer (and sharper) for me now!



May 29, 2015 at 08:41 PM
Peter Figen
Online
• • • • •
Upload & Sell: On
p.1 #8 · p.1 #8 · Questions about Downsizing JPG files for screen and web viewing.


Even Fred Miranda himself had a set of stair step interpolation actions you could download. The results were visibly worse than going in one fell swoop, something anyone can easily test for themselves on their own images.


May 29, 2015 at 09:33 PM
dhphoto
Offline
• • • • • •
Upload & Sell: Off
p.1 #9 · p.1 #9 · Questions about Downsizing JPG files for screen and web viewing.


If you are using a pc this is quite good:

http://www.faststone.org/FSResizerDetail.htm



May 30, 2015 at 04:15 AM





FM Forums | Post-processing & Printing | Join Upload & Sell

    
 

You are not logged in. Login or Register

Username       Or Reset password



This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.