Forums > Photography Talk > Photo stacking manually.

Photographer

Mad Hatter Imagery

Posts: 1604

Buffalo, New York, US

j_francis_imagery wrote:

I would

https://www.dropbox.com/sh/itfsvotf3pz0 … JJyka?dl=0

Hopefully that works.

Sep 19 22 11:59 am Link

Photographer

Mad Hatter Imagery

Posts: 1604

Buffalo, New York, US

As you can see the stacking versions are darker and started losing detail. Any comments? I rather like the B&W technique if only detail can be maintained.

Sep 19 22 08:23 pm Link

Photographer

j_francis_imagery

Posts: 304

Los Angeles, California, US

Mad Hatter Imagery wrote:
As you can see the stacking versions are darker and started losing detail. Any comments? I rather like the B&W technique if only detail can be maintained.

The first method should probably work, but you have to add each group togther with linear dodge or screen.

The second method is getting "crosstalk" from other channels in each channel group, so they are getting desaturated. There is so much crosstalk that they are turning gray:

j_francis_imagery wrote:
If you use more than 3 images and more colors than just pure RGB you’ll end up with a brighter or less saturated result than you probably want.

Sep 22 22 07:13 pm Link

Photographer

j_francis_imagery

Posts: 304

Los Angeles, California, US

I made an unlisted YouTube video

Let me know if you want me to delete it.

Sep 22 22 07:40 pm Link

Photographer

The Other Place

Posts: 400

Los Angeles, California, US

j_francis_imagery wrote:
Perfect CMY reconstruction

Very informative video!  Thanks!

I get a perfect image with this method as well, but the saturation is inverted in each CMY channel, contrary to each RGB channel in the previously discussed methods.

In other words, if I follow the steps shown in your video using GIMP, each channel will have full saturation in the shadows and transition to white in the highlights.  In contrast, when separating (and recombining) the RGB channels in GIMP, the each channel has full saturation in the highlights and transition to black in the shadows.

This inversion of saturation in the CMY channels might result in a noticeable discrepancy between the manner in which the RGB channels and the CMY channels render motion artifacts.  If OP combines RGB and CMY Harris Shutter effects, the CMY motion artifacts might look odd.

I would guess that Photoshop and Paint Shop Pro give the same saturation inversion, but it might be helpful we could confirm whether or not it is true.

Incidently, one can also achieve a perfect CMY reconstruction in GIMP by making three copies of the picture, multiplying one copy by cyan, multiplying another by magenta and multiplying another by yellow.  Then reduce the exposure on each image by 50% (one stop in GIMP), and then addition/screen all of the images together.

Such multiplying of each image by one of the CMY colors does not invert the saturation, but, unfortunately, each resulting "channel" is not pure cyan, magenta nor yellow.

On the other hand, simply using the decomposing to CMYK feature results in each channel being pure and CMY not inverted (the "K" channel is inverted).  So, decomposing/recomposing CMYK might give OP the desired results, if he decides to utilize CMY channels for the Harris Shutter effect.

By the way, in your video, you refer to cyan, magenta and yellow as "subtractive" colors (and to RGB as "additive").  However, there is nothing inherently "subtractive" about CMY (nor any other colors).  That term primarily orignated with CMY filter use in analog photographic printing and in the printing industry.  Using physical filters is a subtractive process, but colors aren't inherently subtractive nor additive.


Mad Hatter Imagery wrote:
As you can see the stacking versions are darker and started losing detail. Any comments? I rather like the B&W technique if only detail can be maintained.

Why are you using the channel mixer?  Split/recombine looks good, as do @j_francis_imagery's RGB methods.

In your first stacking method, you appear to be including six black channels with your three RGB channels.  Your second stacking method gives an interesting result, but you still seem to be including six black channels.


j_francis_imagery wrote:
The second method is getting "crosstalk" from other channels in each channel group, so they are getting desaturated. There is so much crosstalk that they are turning gray:

I'd say that it's more than just "crosstalk" -- OP has every color at 100% in each channel!  Interesting effect, though.


j_francis_imagery wrote:
I made an unlisted YouTube video
https://youtu.be/aOA40CuRMMk

Another helpful video!

Please keep in mind that OP is using Paint Shop Pro, so he might not have "linear" dodge nor some of the other layer blending modes found in Photoshop and GIMP.

Sep 23 22 01:57 am Link