Sharpening

[SandyW]

If I'm going to resize and sharpen I always start with my final version at the original size, resize, and sharpen depending on my intended output. You can sometimes get interesting artifacts(?) when resizing an already sharpened file. On the other hand, unless printing, I seldom sharpen an entire image. I use masks to just apply the sharpening the what I want.

 

[DRwyoming]

I don't understand why you have to resize your image before the sharpening operation; if you don't have to crop anyway your original and you want to have the best resolution during printing, its not preferable to have the maximum Mpx image before printing?

Sounds like you have two related questions there.

In terms of maximum resolution for printing, there's no point in having resolution in excess of what your printer is capable of printing. IOW, if your image is so large that you're sending it to the printer at something like 500 dpi you're not really gaining anything as most if not all printers will have to resample that image to get it to something it can deal with like: 180, 240, 300 or 360 dpi. Don't get confused with the print head dpi rating which describes the resolution micro droplets are printed onto the paper to achieve a pixel, most printers won't print much higher resolution than 300 to perhaps 360 dpi at the image level.

So yeah, it's good to send high resolution up to what the printer can actually handle but higher resolution than that doesn't buy you anything, forces the print drivers to do resampling and just means larger files sent to the printer.

But the second part is why you sharpen at final output size. The basic idea there is that sharpening increases edge contrast by adding subtle dark and light regions around edges in your image. You don't really want to go through sharpening, add those higher contrast edge borders and then resize not only the main image info but also the width of those sharpening contours. IOW, it's best practice to resize your image as necessary for output whether that's print or web use and then perform final sharpening so those edge contours are sized appropriately for the output size.

 

[Cristobal]

Sounds like you have two related questions there.

In terms of maximum resolution for printing, there's no point in having resolution in excess of what your printer is capable of printing. IOW, if your image is so large that you're sending it to the printer at something like 500 dpi you're not really gaining anything as most if not all printers will have to resample that image to get it to something it can deal with like: 180, 240, 300 or 360 dpi. Don't get confused with the print head dpi rating which describes the resolution micro droplets are printed onto the paper to achieve a pixel, most printers won't print much higher resolution than 300 to perhaps 360 dpi at the image level.

So yeah, it's good to send high resolution up to what the printer can actually handle but higher resolution than that doesn't buy you anything, forces the print drivers to do resampling and just means larger files sent to the printer.

But the second part is why you sharpen at final output size. The basic idea there is that sharpening increases edge contrast by adding subtle dark and light regions around edges in your image. You don't really want to go through sharpening, add those higher contrast edge borders and then resize not only the main image info but also the width of those sharpening contours. IOW, it's best practice to resize your image as necessary for output whether that's print or web use and then perform final sharpening so those edge contours are sized appropriately for the output size.

Many thanks for those precisions; I am not very familiar with all the proceedings for exportation in Lightroom; most of the time, my prints have a maximal size of 12'' x 18''; that means that at 300 dpi, I need an image of 20 Mpx, the maximum of definition of my D500; recently I printed some images with a size of 8 x 12', so a final definition of 8.6 Mpx at a resolution of 300 dpi; I can change my definition by cropping the image, but if for example I want to change the definition from 20 Mpx to 8.6 Mpx on Lightroom without any crop before sharpening the image, how to proceed in Lightroom and Denoise Al ?

 

[bjanes]

I will generally sharpen on a duplicate pixel layer assuming I've flattened the image prior to sharpening. There's several reasons for that:

- When sharpening in PS I'll usually switch that top sharpened layer into Luminosity blending mode which tends to result in a bit cleaner sharpened image and that becomes very easy to do when sharpening on a dupe pixel layer as all you have to do is change the blending mode of that top layer with the blending mode pull down menu. I wouldn't bother with this for something like a web post but for a large wall print it can be a useful trick.

The use of the luminosity blending mode on the sharpening layer is a good suggestion. Do you use the blend if sliders to restrict the sharpening to the mid-tones as suggested by Bruce Fraser here? With the newer tools that we have now, Bruce's workflow is a bit outdated but we can still use some of his ideas.

Some posters in this thread dispense with output sharpening, but I think that it still can be useful since some sharpness can be lost when resizing for printing. Personally, I use Lightroom and then edit my image in Photoshop, often using the Topaz plugins, save as a TIFF, and print with my Epson 3880 from LR using low or normal sharpening at 360 or 720 ppi.

Bill

 

[Nikondale]

I try to sharpen very little.

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[Nikondale]

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[dabhand16]

As I understand it, the way and amount you should sharpen depends on what you are going to do with the image. The same image will need different sharpening for printing than for screen display.

For the web and screen display I now use the method in Steve's tutorial

Sharpen And Resize Photos For The Web - Backcountry Gallery

Wanna make your web images look their best? Then you need a good resize and sharpening method! I’ve tried quite a few and discovered there’s a lot more to it than just shrinking down an image and applying a quick bit of sharpening. You need to know the proper bit depth, color space, resize...

backcountrygallery.com

 

[dabhand16]

I don't understand why you have to resize your image before the sharpening operation; if you don't have to crop anyway your original and you want to have the best resolution during printing, its not preferable to have the maximum Mpx image before printing?

I've always been taught that sharpening is the very last step you do. If you have a hi res image that is already sharpened and you make a web sized image from it, the lo res one should also be sharpened. needless to say, the amount of sharpening will not be the same for both images and will be different again if you want to make a print.

 

[Nikondale]

Thanks for the tips on sharpening

 

[SBurkholder]

I generally agree with what most people say here, but I'll add my 2 cents. Sharpening should be the very last step in processing especially after resizing the photo for output. The amount of sharpening you use will very depending on the way the photo will be viewed. If on screen, you will use less sharpening than if it is to be printed. Printing will tend to flatten out the the image a little and the image will need to be over-sharpened to achieve the same effect. LR is aware of this, that you intend to use the photo as a print and will apply this extra sharpening through it print module. Depending on whether you print on Glossy or Matte media will also require different amount of sharpening. That's why the LR print sharpening options are offered. PS isn't aware of where the image will be used and it is up to you to apply the extra sharpening as needed.

Also if using an outside printer, make sure you discuss whether you have added extra sharpening to the photo to compensate for the print process. Because they made add extra sharpening as an automatic step in their resizing efforts. If you want top quality, you should always do your own sharpening, and have the image sized so that the printer will not have to resize it for you and ask that there isn't any extra sharpening or resizing involved on their end. That means you will need to allow for bleed when you deliver the image to them.