Description of PS algorithms

OC
Posted By
Olivier Croquette
Oct 21, 2007
Views
808
Replies
9
Status
Closed
Hi

Is there any site or document where I could find the description of common PS algorithms?

For example, how the 2 source pixels are combined for each of the possible blending modes to give the resulting pixel, stuff like that.

Thanks for your help!

How to Improve Photoshop Performance

Learn how to optimize Photoshop for maximum speed, troubleshoot common issues, and keep your projects organized so that you can work faster than ever before!

Why would Adobe make such propritary information public? They wouldn’t. Why don’t you just ask for the source code for Photoshop while your at it.

The Spider
R
ronviers
Oct 21, 2007
On Oct 21, 11:41 am, Olivier Croquette
wrote:
Hi

Is there any site or document where I could find the description of common PS algorithms?

For example, how the 2 source pixels are combined for each of the possible blending modes to give the resulting pixel, stuff like that.
Thanks for your help!

Hi,
Here is something interesting I stumbled on to just by chance. Create a linear gradient on one layer. On the layer above that layer create another linear gradient at a right angle to the first. Then above that layer create a threshold layer with a level of 128. Then you will be looking at the function of the blend mode between the layers. To see the effects go to the middle layer (the second gradient) and scroll through the blend modes. If you are a mathematical wiz (which I’m not) you might be able to learn something from being able to see the curve profile.

Good luck,
Ron
R
ronviers
Oct 21, 2007
On Oct 21, 2:27 pm, "" wrote:
On Oct 21, 11:41 am, Olivier Croquette
wrote:

Hi

Is there any site or document where I could find the description of common PS algorithms?

For example, how the 2 source pixels are combined for each of the possible blending modes to give the resulting pixel, stuff like that.

Thanks for your help!

Hi,
Here is something interesting I stumbled on to just by chance. Create a linear gradient on one layer. On the layer above that layer create another linear gradient at a right angle to the first. Then above that layer create a threshold layer with a level of 128. Then you will be looking at the function of the blend mode between the layers. To see the effects go to the middle layer (the second gradient) and scroll through the blend modes. If you are a mathematical wiz (which I’m not) you might be able to learn something from being able to see the curve profile.

Good luck,
Ron

I wanted to also mention this link:

http://www.pegtop.net/delphi/articles/blendmodes/

It’s been around a while and everyone knows about it. I heard from a very legitimate source that it has errors but it is a good start.
C
Cliff
Oct 21, 2007
Olivier Croquette wrote:

Hi

Is there any site or document where I could find the description of common PS algorithms?

For example, how the 2 source pixels are combined for each of the possible blending modes to give the resulting pixel, stuff like that.
Thanks for your help!

Some blend algorithms at:
http://www.pegtop.net/delphi/articles/blendmodes/


Cliff
OC
Olivier Croquette
Oct 21, 2007
CJ wrote, On 21.10.2007 21:57 Uhr:
Some blend algorithms at:
http://www.pegtop.net/delphi/articles/blendmodes/

Thanks to you and Ron!
That’s exactly the kind of information I am looking for.
OC
Olivier Croquette
Oct 21, 2007
wrote, On 21.10.2007 21:27 Uhr:
Here is something interesting I stumbled on to just by chance. Create a linear gradient on one layer. On the layer above that layer create

[…]

I tried, that’s indeed interesting!
Not sure there is a lot to learn from that, but it’s a fun way to visualize simply the effects of the blending mode.
OC
Olivier Croquette
Oct 22, 2007
wrote, On 21/10/07 21:31:
I wanted to also mention this link:

http://www.pegtop.net/delphi/articles/blendmodes/

I wonder how many and which of them are really used.
Some must be very hard to master or find a use for.
R
ronviers
Oct 22, 2007
On Oct 22, 12:46 pm, Olivier Croquette
wrote:
wrote, On 21/10/07 21:31:

I wanted to also mention this link:

http://www.pegtop.net/delphi/articles/blendmodes/

I wonder how many and which of them are really used.
Some must be very hard to master or find a use for.

They are all used all the time. I use most of them and different industries or groups use some more than others. For example the Color Dodge/Burn blend modes can be use for rectangular to polar conversion while Linear Light at 50% opacity can be used to subtract two images. Some people want more blend modes but I think if you get good at mixing them then these are enough.
R
ronviers
Oct 22, 2007
On Oct 22, 12:46 pm, Olivier Croquette
wrote:
wrote, On 21/10/07 21:31:

I wanted to also mention this link:

http://www.pegtop.net/delphi/articles/blendmodes/

I wonder how many and which of them are really used.
Some must be very hard to master or find a use for.

Hi,
I just wanted to add to this. First, I’m both an amateur and self- taught so I do not get much feedback about how other people work but because of what I have been working on lately, procedural textures and effects filters, I use blend modes constantly. I have more vision than brains so I never really "master" any of them instead I end up trying fewer in a given situation. For example I almost always know when I will need Screen but if the blend is for effect, rather than something technical like combining masks, I will also check the dodge modes too – same applies to Multiply and the burn modes. I usually know when I will want Overlay but often Soft Light is a good substitute. Difference is one of the most useful and effective for surface maps but so is Normal at 50%. Just because the blend mode name has color in it does not mean it will not be very effective for grayscale maps.

If you want you can look at my textures and effects filters here:

http://www.filterforge.com/filters/author6486-page1.html

If you download the plug-in (the trial is free) you can open up something like ‘Birth of The Orb’ (or any of them really) to see some interesting blending.

Good luck,
Ron

Master Retouching Hair

Learn how to rescue details, remove flyaways, add volume, and enhance the definition of hair in any photo. We break down every tool and technique in Photoshop to get picture-perfect hair, every time.

Related Discussion Topics

Nice and short text about related topics in discussion sections