Reducing size for web - quality problems (1 Viewer)

Hope someone can help me...

I used to use a Coolpix 4500 and never experienced any problems reducing image sizes for posting images to my website, but having now changed cameras I'm experiencing significant loss of quality.

For my website I usually post images at two sizes: 750 x 563 pixels and 280 x 210 and I resize the images in Photoshop Elements (Image, Resize, Image Size). I don't use "save for web" as I don't need to get the file size down as I have a fairly generous allowance with my hosting plan.

With my Coolpix I didn't notice any significant loss in quality in reducing the size - the result was simply smaller but the same quality.

I've now invested in two new cameras, a Coolpix P5000 and a Canon 400D. Performing the same operation I now get a significant reduction in quality. Not sure why this is - perhaps it has something to do with the fact that the image starts off much larger, the cameras having more megapixels, so the reduction is greater? Or perhaps there's something in the settings I've got wrong? Whatever the cause, I'd be very grateful if someone could come up with a solution.

I've noticed that when I post the same, unsized, images to Flickr, the automatic resizing that Flickr performs does not result in the same loss of quality.

Examples:

Coolpix P5000 Bittern:

• Initial 3518 x 2640 (as posted on Flickr)
• Resized by Flickr 240 x 180 - quality is the same as far as I can tell
• My attempts at resizing with Photoshop to 750 x 563 - some loss of quality but not especially obvious at this size
• Additional resizing with Photoshop to 280 x 210 - obvious loss of quality - this image is worse than the smaller 240 x 180 image on Flickr

Canon 400D Stock Dove

• Initial 852 x 640 as posted to Flickr
• Resized by Flickr 240 x 180
• My attempts at resizing with Photoshop to 750 x 563 - some quality loss evident
• Additional resizing with Photoshop to 280 x 210 - much worse than Flickr's smaller 240 x 180

Someone suggested reducing the size in small amounts rather than in one go. Have tried this and it does seem to improve slightly, but not enough.

Any ideas?

Generally speaking, you need to sharpen any picture after a resample downsizing. Often I find with Paint Shop Pro, the simple sharpen tool (no options, just does it) is about right to restore it to original sharpness. Sometimes I use Unsharp mask to have more control. But it is almost always necessary.

As far as other "quality" attributes - saturation, contrast, etc, I have not found that these are worsened by downsizing.

Not by any means an expert but offer the following.
Point & shoot cameras have in-built facility which will automatically improve the photo i.e. contrast, saturation and sharpness etc. With the 400 you will need to do this yourself.
I use a simple programme called photofiltre. The 3 main sections I use are brighter/darker-saturation, contrast & sharpen. I then use 'image' and downsize to 800 x whatever it tells me.
Hope this helps

Thanks.

I usually sharpen the image slightly before resizing, but have tested unsharpened images to make sure it's not just this - and it doesn't seem to be. If I sharpen the image after resizing, instead of improving the image it exaggerates the problems.

Have experimented comparing the 'resample: bilinear' option instead of the default 'bicubic' and seeing if having saved the image at 750 x 263 before further reducing it to 280 x 210 makes a difference compared with reducing it in one go. There may be slight differences but they're subtle compared with the overall problem.

Dave,

Not sure what the issue is withou "looking over your shoulder", but one guess is that maybe when you resize the image, the compression setting for jpeg might be too high?

My basic workflow in Photoshop is once I have finished working on the file, I either do a "Save As", or duplicate the file to avoid destroying the original. For the web, I save the image as 600 pixels wide at 72dpi using the Edit>Image size menu.
I then use a small pass of unsharp mask on the file (Amount:c.150, Radius:c.0.4 Threshold:0) and I'm done. I usually use a compression setting of about "6".

Sharpening should always be the last step performed after resizing an image for output, but when I save my images for the web, I always add a low amount of unsharp mask to bring optimize the image.

Thanks Julian. I think I must have a different version of Photoshop, maybe - I'm using Photoshop Elements that came with the original camera. I can't see any options for compression settings anywhere - am I being blind or looking in the wrong place, or is it just not available on my version?

Your unsharp mask settings are useful anyway: someone once told me their optimal settings which worked well for me until I lost them - experimenting with the different levels I never could get quite such good results and I think your settings are better than what I've been using.

Every time you save a jpg image it loses some quality, it's the nature of the file system.
However, as Julian says, you can minimize this by saving at the highest quality, and as a copy of the original. When you save the final image as a .jpg it should give you a quality option slider from 1-12, just select 10 or higher to retain quality.

As for sharpening, it should always be the last process before saving, and definitely done after resizing not before.
My favoured setting for smallish resized web images are very close to Julians, usually Amount: 100-150%, Radius 0.3-0.5, Threshold: O.
Requirements vary according to the image, and sometimes I find using the lasso tool to draw around the subject, and then only sharpening that area, produces more "punch" and helps the subject stand out from the background.

You will usually find that DSLR images require more sharpening than compact cameras', as the in camera sharpening is quite strong on many compacts.

Cheers,
Matt

If you use the Save for web option you should have all the control you need. you did not say which version of elements you have but I'm sure they all have this.Regards Edd Willis

What you should be doing is this---If you shoot JPG in camera---Once in the Folder on HDD you open it in your Photo Progy---You Imediatly do a "Save As" TIFF...You do NOT touch the original Jpg file..NEVER......You work on the Tiff file, sharpen last, and when it's finished you then do a copy ...You can then do a re - size of what you want then ,
"Save As" JPG--Name it.

Thanks for everyone's help on this. I eventually found out what I was doing wrong. When you Save As you get the option of changing the quality level on a scale of 1 to 12. I'm not sure but I think doing just Save saves it at the same quality you last selected when you last did a Save As. I don't think it's as simple as just remembering the last time you did Save As however, as it seems to revert to a lower quality level when editing an image which you'd previously edited. Anyway, for some reason the quality level had reduced to 3 instead of 12, so every time it I saved it was massively reducing the quality. So it wasn't the resizing itself that was causing the problem as I'd assumed, but the saving after I'd resized the image.