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High pass filter?
Posted: Tue May 18, 2004 2:29 am
I found an interesting web site that describes a process that creates a digital representation of an effect I used to get in the darkroom called "lithographic derivation." The result looks like a line drawing, but with some detail.
The process requires a PhotoShop filter called "high pass." However, I use Jasc PSP, which doesn't include one. I've had no luck searching for a plug-in with parametric high pass.
Any suggestions? Free or pay, doesn't matter.
Posted: Fri May 21, 2004 12:42 pm
Actually, you don't need a filter to do high pass. All you need is Gaussian Blur and Invert:
1. Copy the original layer into a separate layer
2. Place the copy layer over the original
3. Blur the copy layer using Gaussian Blur
4. Invert the copy layer
5. Set the transparency of the copy layer to 50%
Posted: Fri May 21, 2004 8:00 pm
Interesting. But you get a more accurate Highpass effect if you additionally use the Linear Light blend mode in Photoshop. That blend mode isn't available in PSP, but the Normal blend mode will do, too.
Can you please share the URL about the lithographic derivation, Doug?
Posted: Sat May 22, 2004 7:51 am
There is also an excellent article about the High Pass on Gamasutra:
Posted: Tue Jun 01, 2004 6:22 am
Paint Shop Pro 8 has a 5x5 Highpass and a Highpass plugin listed under the User defined plugin listing.
Posted: Sun Jun 15, 2008 3:41 pm
ok, this is an old thread, but it's awesome. thanks... nothing better than keeping it simple when it comes to effects