• Please use real names.

    Greetings to all who have registered to OPF and those guests taking a look around. Please use real names. Registrations with fictitious names will not be processed. REAL NAMES ONLY will be processed

    Firstname Lastname

    Register

    We are a courteous and supportive community. No need to hide behind an alia. If you have a genuine need for privacy/secrecy then let me know!
  • Welcome to the new site. Here's a thread about the update where you can post your feedback, ask questions or spot those nasty bugs!

Moving Water by Scanning Digital Backs rainbow artifact

Asher Kelman

OPF Owner/Editor-in-Chief
We are used to the two approaches to moving water with film: blurred v. sharp pictues isolating single water drops.

The scanning backs of yield, IMHO some of the most spectacular pictures ever with unending resolution at economical prices!

However, the rendering of moving water brings new artifacts with all this wonder.

From this thread,

http://www.openphotographyforums.com/forums/showthread.php?t=571&page=2

We are introduced to a Rainbow effect in moving water by Jack Flesher's images here

http://web1.omniblog.com/_smartsite/modules/home/showcase.php?uid=102

The rainbow effect I didn't see on Jim's pictures of the beach. http://collum.omniblog.com/

I see this is a big challenge.

1. What solutions do people have for this unattactive artifact in otherwise breathing photography?

2. Is it related to the color effect seen present on the pictures of white flowers too?

Asher
 

JimCollum

pro member

Asher Kelman

OPF Owner/Editor-in-Chief
Jim,

I looked as carefully as I can but I can't see any rainbow effects in the moving water.

Perhaps it is the height of the spray and the relative position of the observer and the sun that causes the effect in Jack's water fall pictures. Or else, in your wave pictures, the magnification it is viewed on with my screen doesnt allow me to see a rainbow effect that might be there.

I tried to look at the images in PS but the images are .php files which won't open!.

Do you see any rainbow effects in magnifications on and above the waves?

Asher
 

Jack_Flesher

New member
The fact that the rainbows in the waterfall crops I showed above themselves look like the "normal" rainbows we see in waterfalls, their true nature is camoflauged. I am pretty sure those are motion artifacts however, as they are inside the shadow area of the fall where the sun had not yet hit. (Of course, this in and of iteself can be an argument that they are not objectionalble!)

Perhaps these crops will better show the rainbow effects in moving water Jim and I are talking about: This first image is another 600x800 actual pixel crop (1/100th of the total image) showing the rainbows in moving river water. They are out of focus as the focus plane of my large format camera was centered on some trees in the mid-ground and I could not impart enough tilt to still keep the falls in the background and these ripples in focus:



Here however, is a screen capture at "print resolution" of about 16x20 inches at 360 PPI. I think this is perhaps where the discussion can continue as to the "trouble" these rainbow motion artifacts create for the viewer of the image:



Personally, I don't find them objectionable and prefer to think of them as an alternative representation of motion. Granted, it is not the one we are used to seeing, but more and more I am leaving these in my Betterlight images. Perhaps people seeing *my* work will come to accept them as "normal" over time :)


Cheers,
 

Asher Kelman

OPF Owner/Editor-in-Chief
Monet!

I like it.

Jack, you started me on a bunch of steps of education Thanks!

Normally, one has to add paint to an inkjet print to get this efect! Here its is so unique and it adds a splash of artistic movement to the water.

Thanks for going to the effort of finding the samples.

Now what about the white flowers? They also appear to have some chromatic effects, but more diffuse.

Is that in the flowers themselves, akin to colors brought out by UV light in certain flowers? Or is it an artifact?

Asher
 
Last edited:

Jack_Flesher

New member
Asher Kelman said:
Monet!

I like it.

Jack, you started me on a bunch of steps of education Thanks!

Normally, one has to add paint to an injjet print to get this efect! Here its is so unique and it adds a splash of artistic movement to the water.

Thanks for going to the effort of finding the samples.

Now what about the white flowers? They also appear to have some chromatic effects, but more diffuse.

Is that in the flowers themselves, akin to colors brought out by UV light in certain flowers? Or is it an artifact?

Asher
You are quite welcome Asher!

As for the "white" flowers... First off, they are not white! (At least not in normal, visible light!)

Those subtle hues are brought out under the IR -- IR as in InfraRed and I make the distinction against UV (UltraViolet) which is a common misstatement.

The Calla lily is of course mostly white -- yet on a good, properly calibrated monitor you will see subtle hues of yellow/gold -- and of course the cyan in the greens.

The first orchid is mostly light-pink with dark red spots and a yellow-orange center (!)

The second orchid -- as best I recall -- was a soft lavender, again with a yellow to orange center.

Some of the iridescence you see is only visible in the web jpegs, so I suspect it is a banding issue during the colorspace conversion to s(mall)RGB.

Cheers,
 
Last edited:
Top