By rusteberg
#322240
This just surfaced today, see example below. More sss noise is showing up with the photoshop emitter intensity than with the emitter intensity within maxwell render?

MXI in maxwell render with single emitter on
Image

Same mxi inside of photoshop with exposure increase on same emitter visible in maxwell render interface
Image
User avatar
By Brany
#322471
The photoshop's exposure tool is not equivalent to the maxwell's lights sliders! Realize that image exposure and light power aren't be the same concepts ;) You should use low exposure values because the effect of the exposure tool is pretty hard. If you set the light value to 1.000W or 10.000W instead 250W in maxwell you probably will obtain the same noise. In some of our test, an exposure value of 6 in photoshop came to be equivalent to a 1.000.000W light in maxwell!

Photoshop SDK doesn't provide enough functionality to develop a properly easy-to-use multilight filter...
User avatar
By polynurb
#322482
Tom, what does the PS image look like when converted to 16 or 8 bits?
By rusteberg
#322488
ahhhhhhhhhhh.... thanks for the feedback brany.
daniel, it actually looks a lot better when converted to lower depth as i just found out..... had no idea you could still adjust intensity and color value below 32bit :oops: .

thank you both of you for setting me off in the right direction!
User avatar
By polynurb
#322534
polynurb wrote:Tom, what does the PS image look like when converted to 16 or 8 bits?
i didn't mean to sound clever here... i was really curious how your particular image behaves when converted to lower bit depth!

search the forum for "hdr and aliasing" back from 1.71... and i would assume that what we see i your image is due to similar display limitation of HDR data on standard computer screens.

when viewing an mxi via maxwell.exe, my guess is that it takes care of the proper conversion and displays the brightness clamped to something within the display range, but when saving as hdr and opening in PS, some detail in bright areas might look different, more exposed or aliased along very contrasty edges.

if you move the exposure slider in PS (the slider at the left bottom corner of an image if in 32bit mode), you will see a lot of banding with many hdr (even with very good ones!)... it will go away once converted..., but ultimately only editing in 32 bit will give you access to the full information of the mxi.

there are a few hdr conversion methods (when going 32>16bit) in PS that might help with such overexposure.. like local adaptation or highlight compression which then can be recombined with the original HDR to get rid of certain unwanted artifacts.. at least that is how i do it..
By rusteberg
#322729
polynurb wrote:
polynurb wrote:Tom, what does the PS image look like when converted to 16 or 8 bits?
i didn't mean to sound clever here... i was really curious how your particular image behaves when converted to lower bit depth!

there are a few hdr conversion methods (when going 32>16bit) in PS that might help with such overexposure.. like local adaptation or highlight compression which then can be recombined with the original HDR to get rid of certain unwanted artifacts.. at least that is how i do it..
no worries, i read it as constructive advice/guidance.

this is all new to me, so i'm not clear on the latter part where you mention local adaptation/highlight compression workflow. any good links or examples you know of that would help me understand this process? thanks!
User avatar
By polynurb
#322734
the process is pretty well explained in here:

http://www.cambridgeincolour.com/tutori ... -range.htm

since adobe didn't include a curve editor for 32bit mode, (i think cs5 has it) the best method for getting various info from the 32 bit was the toning curve option you get when you choose "local adaptation" in the conversion menu and click the little arrow to show the histogramm, there you can edit the curve!
having a 32bit file open, click on mode >16 bit (your document needs to be flat/single layer, or the dialog won't show)

cheers,

d.
By rusteberg
#322766
Wonderful link. Thanks for posting that Daniel!
Btw, when am I going to get to see some more of your exquisite renderings?
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