Denoise in Photoshop and High ISO

[pschlute]

Recently I have found details are sometimes enhanced by adding contrast via a duplicate Photoshop layer and blending with Overlay or Soft Light modes then reducing the opacity or flow. But this may be pure perception rather than a true side effect of that process.

I could well be wrong, but I think that is the reasoning behind the "Unsharp Mask" method of sharpening an image.

One that well predates the digital age I may add !

[Manfred M]

In terms of sharpening, would you treat a projected digital image differently to one that is to be viewed directly on computer screen?

Answer is absolutely yes!

When viewing on a screen, the size of any specific screen is fixed. When printing, the size of the final print is variable. In general, the resolution of screens, especially for images we see on web browsers is quite low (generally to have short load times).

I find that any time I make prints that are equal to or larger than A4 / 8" x 10", sharpening becomes important. In general, it is easier to "pixel peep" a print than a screen.

When I post-process, I generally work at the full resolution of my digital image and save it as a "master file". I then resize that file for output, which is device dependent. I usually work in the the ProPhoto RGB 16-bit colour space and for digital output I use 8-bit sRGB, usually around 1920 x 1080 pixels in size. I generally find that I don't need to sharpen these images as the downsizing algorithms already enhance micro-contrast.

When printing larger formats, I generally need to upsample the image and that process does create a bit of softness that needs to be countered by output sharpening. I typically use the Unsharp Mask tool (fewer variables to worry about than Adobe's SmartSharpen). I view at both 100% size and 50% size on the screen when sharpening to find the "sweet spot". Unfortunately, this is really about opinion and I have yet to find that a formula based approach works for me.

An image with a lot low frequency content often needs less sharpening (we don't need "crunchy skies or water"). Same problem occurs with high frequency content (rocks or pebbles on a beach or leaves on trees), again over-sharpening can result in an image that is not to my taste. Deep shadows or bright highlights, also look strange when they are sharpened and in my workflow I use Photoshop's blend if algorithms to exclude blacks and very dark grays (values below 20) or whites or very light grays (above 240). I use a gradient between values of 20 and 40 and between 220 and 240. It sounds complicated, but isn't really. This process doesn't have to be 100% exact as I see little difference if I miss these number by 5 or even 10 units.

I throw out the output file when I am done because it only takes a few minutes to create a print file and I don't need to waste disk storage space on these files.

I will apply layer masks at times to control

[Manfred M]

What a great question.

Most of the big photography exhibitions I visit are turning more and more to digital display, so I am interested in the answer too.

I've heard Europe has gone that way, but so far in this part of Eastern North America, thankfully they still display prints.

I personally find that the framing solution used by the photographer is an important aspect of the final work, A large screen with black bars somehow disrespects the artist and makes the work look second rate.

In the series of prints that I currently have showing in a gallery, the frame colour, design and glass, as well as the background of the gallery wall all play an important part of the look and feel I wanted to create. The lower gamut of the screen doesn't help either as the paper I printed on has a lot of colours in the ProPhoto colour space that just don't come across as nicely in a high definition television running the video equivalent of sRGB (i.e. Rec. 709). I look forward to screens with full Rec 2020 colour space support.

[Rufus]

Manfred - your posts #22 and #23 are very helpful.

And in the worst case when a digital projector is used, it may be in poor ambient light conditions and the projector may even maginally out of focus. That is the definition of truly frustrating. You are fortunate not to move in such circles!

[pschlute]

Manfred - your posts #22 and #23 are very helpful.

And in the worst case when a digital projector is used, it may be in poor ambient light conditions and the projector may even maginally out of focus. That is the definition of truly frustrating. You are fortunate not to move in such circles!

Just to be clear, when I refer to "digital display" for a photography exhibition, I mean each image is displayed on it's own display monitor (hanging on the wall as if it were a print). Not projected like a slide exhibit. The exhibition hall is of a uniform very dim lighting. They look good, but Manfred makes some important points about framing and photographers intentions, which may make this kind of display unsuitable for some.

The middle of this page shows an example..... https://www.nhm.ac.uk/visit/exhibiti...-the-year.html

[Rufus]

The middle of this page shows an example..... https://www.nhm.ac.uk/visit/exhibiti...-the-year.html

In the examples, the gallery reminds me of a nature reserve hide