Digital Light & Color

Maciej,

"if you sandwich it through the reversed brightness mask"

Could you explain this a bit more, please.

Tony

TonyG/MaciejT... Others

A screen shot of what I have been doing to add distributed noise based upon an image's luminance as described in my prevous posting above is here: http://www.ncplus.net/~birchbay/misc/Ad ... dnoise.htm... ...hope this is of help.

Den,

I've tried your route but, like you, I have yet to produce a convincing result.

Maciej,

You said "I'm not sure what's optimal, but at least in one case it really looked like a grain"

I can't wait to see that when it's for public consumption!

Tony

TonyG...

Do you have specific image you would like to add noise to? While I did not review in detail all of the links that were given for examples, the last sticks in my mind as rather dark and morose in ambience inviting strong dark contrast and grain... which may be the best type image to add grain to rather than one of my low ISO, low noise landscapes.

Also, I still believe, that a digital grainy image should be planned... pre-selecting the ISO to a high setting and ambient or studio lighting with moody ambience in mind which seems to be the methodology of the last linked photog.... rather than converting an image that may have had a different goal originally.

Also, it is not clear to me... is the goal for a grainy BW or a grainy color image? Then to, strong, dark contrast will show existing grain more than normal brightness, so that adding additional grain may not be needed.

To avoid the uniformity of tiled textures, here is a link to a 3119x4679 pixel tone map image of ASA400 grain [warning; 11.8 MB file size]: http://byscuits.com/grain-tm400.png that may be of interest.

Den,

Not ignoring you. Just rather dominated, photographically, by several 'asap' requests.

I think I have a nice low ASA shot of Bosham, that might make an interesting High ISO challenge.

I'll find something soon.

Tony

Jonathan/Tony/Others…

I was not able to get preference final image versions when using the Halftone transformation… for me, they seem to result in too much regularity in the applied halftone texture patterns… even with the texture type that was suggested… texture size seems to need to vary with an image’s brightness [HSV-V] as well as the texture brightness/contrast…

Along those lines, there is a way to map grain size based upon an image’s highlight, mid-tone, and shadow tone ranges by:
(1) Develop fine, medium, and coarse grain texture images that register to a ‘starting image’;
(2) Develop symmetrical Highlight, Mid-tone, and Shadow tone range masks of the ‘starting image’; and
(3) Use StackImages where the Input images are the registered grain texture images and the Amount masks are the symmetrical tone range masks; matching Fine with Highlights, Medium with Mid-tones, and Coarse with Shadows; to produce a mapped grain texture image…

Then use the mapped grain texture image as the Overlay in the Composite-SoftLight transform where the Input image = the ‘starting image’ and the Input Mask = the ‘starting image’s’ Invert-ed HSV-V channel [the MaskTool-BrightCurve= the default [0,0], [100,100], ‘lower-left’ Apply Add, Invert]… adjust the Composite-SoftLight Amounts to preferences, then click OK.

Adding a darkening, contrast ‘s-curve’ to the resulting image will yield in most cases, a believable, color or color converted to BW, image [portrait or nature landscape] with added HSV-V noise brightness and grain size distributed throughout the image based upon its original brightness [HSV-V].

Illustrated below is a cropped image area of a ‘starting image’ and its resulting image with added HSV-V grain [noise] converted to BW (aggressive for illustration purposes):

Den,

Foregive me for not posting an image for experimentation. I certainly will.

I took some time out in a bookshop yesterday looking at some books of the work of people like Sebastiao Selgado. Google quickly finds some reasonable sized examples.

Is not the difference between his prints and that portrait above in the fact that you have 'grain' in the highlights and you would not get that with film?

Tony

Tony...

Easy enough to soften the aggressive darkening contrast and sharpness of the illustration to another preference... but my preferred levels would not show anything at the resolution required for posting....

Looking forward to another image with perhaps a preference listing as a guide... perhaps a DL-C challenge?...

This may be of interest. I haven't tried to figure out how it does it. The trial download is ~100Mb.

http://www.dxo.com/intl/photo/filmpack/ ... k_examples

As things are a bit slow... I will bump this thread as I have come across a PS plug-in freeware that has some bearing on the thread discussion...

The plug-in is "virtual Photographer" and can be run from "virtual Studio" if you do not have PS plug-in platform:
http://www.optikvervelabs.com/

"vP" has a film tab that will let one choose contrast curves for 2 film types and 2 slide types; as well as adjust brightness and contrast; and the selection ASA type grains with amount adjustments... Just how realistic the results are is any one's guess but then the "price" is right, "Free"... certainly do not expect results equivalent to MaciejT's suggested software link.

The draw back is that the plug-in only functions with 8-bits per channel [24-bit color]... but if you do a Composite-Blend in PWP with the 48-bit color starting image and the "vP" image as the Overlay... you will retain a 48-bit color image...

There are a number of color and black/white [tint] presets that may be of interest as well....

Have fun!....