Avoid Blurry Previews

A often heard complaint from people evaluating PhotoLab for the first time is that the Preview generation creates blurry previews, while development settings are changed with the sliders in the “Customize” area. This feels like a blackout and is often perceived as bad performance. This looks like this:

Looking at the same time into the task manager, it is reveiled, that the CPU is almost sleeping, although all cores are used:

The request is to improve the preview generation architecture, so that the visible image part never becomes blurry, while dragging the development sliders. An inaccurate preview is OK, as long as the user does not zoom to 100%. At 100% the changes should be calculated on the visible image part only, which is much smaller than the screen resolution.

I find this also quite important since the eye has to get accustomed to the photo every time anew the picture becomes blurry. In addition, I also find that the preview should be sharper in general. Is DxO PhotoLab directly working with the RAW files for showing the changes we make in the program? Would usage of thumbnail files for the actual preview make DxO faster? :thinking:

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I think that an intermediate image is used with a resolution much smaller than full hd, to preview the changes, while the settings are applied to the original data in the background. When the algorithms are done with the raw, the low res preview is exchanged by the hi res one. The visible image part does not seem to be taken into account, because the preview also gets blurred when the user changes adjustment after he zooms in completely.

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I agree that the blurry transition from one modification to another is a visual impediment. Couldn’t there be a small animation of some sort that indicates the image adjustments are being processed - similar to the “Export to disk” indicator.

There are two indications:

  1. The text ‘Correction preview’ in the upper left corner
  2. The spinning donut in the lower right corner

See screenshot

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Yes & to clarify: just use those types of indicators & skip the blurry transition.

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I actually can’t see why there has to be such a long delay of showing the slider effects or a delay at all. Sure, picture modification is a demanding process in terms of PC horse power, but other programs such as Capture One for example immediately show the modified picture upon using the sliders. A simple “more contrast” action can’t be that demanding.

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i am not have much experiance in different applications but the one am used to before dxo had a realtime rendering on screen, this you could activate or not, and you got after every time you did something to the image like sharpening or other rendering action like noisereduction, it divided the image in blocks of 1/8 of the screen and you see rebuilding block by block, and my pc was rather fast.
So i personally find it not disturbing what dxo does. The only thing i would like is a full screen preview of primenoise result as a toggle function, so you can just zoom in where you like with the hand. now you need to move the previewbox around. by toggle fullimage preview you don’t have the delay all the time. like a checkbox in noiseredeductiontool.
same as the chromatic aberation and purple fringing, its in full image often stil visible and when zoomed in on that section it disapears because the aberationremoval kicks in.
this is also to speed up image building on screen i think.

Did you try to adjust fine nuances of micro contast? There you can only guess what will be the result.

i got behind my pc and tested micro contrast.
Just moved that specific slider: -100 goes blurry and +100 does goes oversharpend.
even when you wait a longertime its stays blurry, so i gues that the microconstrast lowering in the minus causes blurring and as microcontrast and fine contrast is used for sharpening that behaviour in the image seems to be right. and it react fairly instant.
Or i just mist your point compleetly :blush:

I think what he meant is that you can’t properly adjust the microcontrast or clearly see changes in microcontrast when the picture gets blurry everytime during slider usage.

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did some extra test and
ah now i get the problem: if you keep your mouse leftclick down it STAYS blurry and don’t represent the real microcontrast rendering.
You have to let go the left mouseclick to see what you change did.
Yes that is indeed very anoying. every smal adjustment needs a lose the click ,watch activate click shift, lose the click and so one.
(as a workaround you can use the arrow up and down next to the digit. i tested that and then it is fairly direct visible. Don’t use the slider as adjusttool but the arrows next to the digit.)

My other application does real time rendering wile hovering over the options and holding mouseclick down doesn’t stop it from rendering.

Same as with choosing WB or so: hoovering over the row of choise doesn’t reveal its outcome, you need to click it before showing on screen. and clicking means selecting.
hoovering and show would be much better, so you don’t have to select to see a other colorprofile by WB or preset.


Yes this is exactly the problem I mean. You always have to do the Press-Move-Release-SeeWhatYouGot cycle. This is true for every slider.

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I use it like this and I have no blurr effect.


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Wow! All these years all I needed to do was let go of the left mouse btn! :smile: