Question on Resizing Photos

[mwilson263]

Hi all,

Fairly newbie question...When I edit a photo (I use Photoshop) I save it as a full size file. The last thing i do is resize it for web and save it as such for social media etc. I've heard that when you crop or resize a file you should always use unsharpen mask as a final step prior to saving. I've never done that. Could someone explain why this would be necessary and what it corrects? I'm not completely understanding it.

Thanks, Mike

 

[Ysarex]

Hi all,

Fairly newbie question...When I edit a photo (I use Photoshop) I save it as a full size file. The last thing i do is resize it for web and save it as such for social media etc. I've heard that when you crop or resize a file you should always use unsharpen mask as a final step prior to saving. I've never done that. Could someone explain why this would be necessary and what it corrects? I'm not completely understanding it.

Thanks, Mike

To begin with what you've heard is questionable and at least needs a lot of clarification.

Sharpness is a tricky business. That's because how you sharpen, when you sharpen and how much you sharpen is output dependent. If you take a photo and print it say B4 paper size and also upload it to Flickr for people to view and also email out a copy for friends and family to see on their phones you have three different uses that ideally should be sharpened three different ways; eg. the sharpening needed for the print would be wrong for the email version.

The above assumes that the photo isn't already sharpened for some other use. Sharpening can't be undone and changed to another output use. So if you have the already sharpened print version of the photo you can't convert that into the email version. To get the correct email version you need to go back to the unsharpened original.

Let's back up to Photoshop when you resize the photo for web display. What algorithm are you using for the resizing? That will effect whether and how you sharpen the result. In the Photoshop Image Size dialog there's a dropbox where you can select the resizing algorithm -- you've got 1/2 a dozen choices some of which sharpen the image in the process and some which do not. Are you using the right one for your intended output target assuming you do or do not plan to sharpen the result?

Yep, it's enough to write a whole book about: https://www.amazon.com/World-Sharpe...4&sr=8-1&keywords=real+world+image+sharpening

So back to your original question. You say when you edit a photo you save it full size. Is that image sharpened and if so how? Is it a camera JPEG that was sharpened by the camera software or is it a raw file sharpened during raw conversion and backing up even further is it from a camera with or without an AA filter? Up to that point we call any sharpening applied to the photo input sharpening and the standard practice is to keep that light-handed in preparation for output sharpening that will be target specific. A whole lot of folks screw up the input sharpening end of the process (over-sharpened camera JPEG for example) and so render the output sharpening question kind of moot.

Then yes, depending on the input sharpened condition of the original and the algorithm used to accomplish the resizing you typically want to apply some output sharpening to a final image prepped for web display.

Joe

 

[mwilson263]

Wow, thought this would be a simple question...my head is spinning.

I shoot in raw, and do some editing in adobe camera raw before I bring it into Photoshop (Elements). Part of that usually involves adjusting the clarity in the raw file, though honestly I adjust to how it looks good to me, I don't really know what I'm doing. Once I bring it into photoshop I make the adjustments I want - crop, color adjustments etc; and sometimes, but not always, unsharpen mask (though again I'm not 100% clear in what I'm doing). I then save the file as a JPEG & print off of that if it's print worthy - usually 4x6, sometimes 8x10, and I just the other day printed out my first B4 size print (which I think turned out amazing).

I then take that JPEG, resize it usually to 1200 x 800, and save it in an "web" folder on the computer. I've never noticed that dropdown before - it defaults to Bicubic (best for smooth gradients) so that's what I've always used.

So for each image I edit I have the raw file, large JPEG, and small JPEG. On a rare occasion I'll save as a PSD file, but usually not. I use social media (mostly FB) far more than I print.

I've never been really sure about whether my post workflow makes sense, or if there's a better way. I probably just need to do some more research and study on the subject so that I actually know what & why I'm adjusting - will check out the book you linked to. I think I would benefit in some general Photoshop tutorials as well instead of winging it.

Thanks so much for your help & input, I really appreciate it.

Mike