This adobe photoshop tutorial will teach us how to post process our picture to create a perceived dynamic range increase.
From here on all that is written is just a copy/paste from PhotoKan’s tutorial
For quite some time now I have been applying and perfecting this PS technique, I learned some time ago and that, when judiciously used, caters for a perceived dynamic range increase, much like Sonyâ€™s DRO or the â€œMerge to HDRâ€ routine in PS CS2 (…which, quite frankly, I have still to try, since it seems to require a big number of exposures to work and, I suspect, requires a lot of time and processing powerâ€¦).
I have been told it kind of emulates the way the human eye works regarding dynamic range perception (ophthalmologists come forward pleaseâ€¦). Don’t really know about that but it works fine and, if one shoots with it in mind, noise in darker areas can be kept under control.
It can be done with a Jpeg shot but, for obvious reasons, Raw is the way to go, especially because the whole procedure can be applied in a 16bits/Channel environment in PS.
(All commands for a PC)
1.Stack the â€œLightâ€ version on top of the â€œDarkâ€ version by dragging it while pressing “Shift”.
The â€œLightâ€ version is now a layer on top of the â€œDarkâ€ original. You may close the â€œLightâ€ original, once the stacking is done.
2. Add a layer mask to the top layer (the “Light” version). You should now have something like this.
3. Select the â€œBackgroundâ€ layer (the dark one). Press â€œCtrl + Aâ€ to select all of it.
4. Press â€œCtrl + Câ€ to copy the whole image.
5. â€œAltâ€ click on top of the MASK next to the top â€œLightâ€ layer. This will select only the mask for display. It will be all white.
6. Press â€œCtrl + Vâ€ to copy the image content into the mask. It will appear as a black and white version of the lower image.
7. Press â€œCtrl + Iâ€ to invert the black and white image into a negative rendering (because we put the lighter version on top of the darker one. This particular step can be avoided by stacking them the other way around but I prefer it this way).
You should see something like this:
8. With the mask still selected, select â€œBlurâ€ -ïƒ â€œGaussian Blurâ€ from the â€œFilterâ€ menu. Choose a blur radius between 15 to 50 pixels. I like to use 25 but you should experiment.
It will now look like this:
Click back on top of the â€œLightâ€ layer image and toggle the layer visibility icon (the little eye) between ON and OFF to see the effect (layer mode should be set to â€œNORMALâ€). Adjust opacity to suit taste and select â€œFlatten Imageâ€ from the layers drop down menu.
â€œVoilÃ¡â€ instant increased dynamic range!
You can try some variations of this, like using 3 different â€œexposuresâ€ and combining them 2 at a time.
Also, you may duplicate the â€œlightâ€ layer from step 8, combining the 2 first layers in â€œNORMALâ€ mode and them, again, combining the resulting layer with the processed â€œLightâ€ layer but this time in â€œScreenâ€ mix mode with a reduced (10-20%) opacity.
Sometimes, between step 7. and 8., I select the â€œLevelsâ€ box, with the mask still active, and use the provided white and black droppers to exactly set minimum highlight areas of the photo I want concealed and the maximum dark areas I want revealed.
Hope this may be of use to you guys.
Original thread can be found here