June 10, 2006

Color Illusion Tutorial


I put up a tutorial for the Spanish castle illusion.
There's a PhotoShop action on there too.

35 Comments:

Blogger Sereena X said...

You shouldn't tell them. You should make them pay.

I am a mercenary.

But thanks for sharing. Maybe I'll try to make one of those illusions. Your instructions look easy to follow.

6/11/2006 8:23 AM  
Blogger John Sadowski said...

Well, I had my 15 minutes of fame for that illusion!
Time to pass the ball. Or baton. You know what I mean.
js

6/11/2006 1:54 PM  
Anonymous Anonymous said...

I tried to follow your directions, but it wouldn't work for me, neither would the photoshop action that you created. I noticed you're using a Mac, is there a difference between Photoshop CS For PC and Photoshop for Mac? You can email me back at drgnlovr25@woh.rr.com if you would like.

6/11/2006 2:14 PM  
Anonymous Thad said...

Can you do a tuturail in Polish because I don't speak, read, or write English!!!!

6/11/2006 6:28 PM  
Blogger John Sadowski said...

Florian Sander from Germany e-mailed me and pointed out that my Photoshop action won't work in non-English versions.
They use a different name for "background image."

He also created a "simple rollover-generator for those who don't know how to create this effect or don't have a html editor with this feature."

Thanks Florian! ~ JS

6/11/2006 6:56 PM  
Blogger John Sadowski said...

If you're running IE, Splasho.com created an illusion generator based on my illusion. (It doesn't work on Macs at all.)

I think it would be relatively simple to create a Dashboard widget that creates this effect to an image dropped onto it. I think all the filters are available in OS X's built-in Core Image technology.

6/11/2006 7:58 PM  
Anonymous Anonymous said...

I would like to correct my previous post that I posted as to my not being able to create an illusion using your guide. I gave you the wrong email address. my correct email address is crazycory25@woh.rr.com
Thank you

6/12/2006 4:08 AM  
Anonymous Mike said...

nice blog you have there, I loved the purple site also :p

6/13/2006 11:13 AM  
Anonymous Anonymous said...

Is it just me, or do red objects simply not show up in color? For the life of me, I can't see red objects when I do this - if they have any color at all, it's very, very faint. Most of the time, they're just black and white - while I can still see the rest of the image in color.

6/13/2006 12:23 PM  
Anonymous wesley007.5 said...

you are right i don't see the red color 2. i can see all the other collors but is can't see the red one it's verry strange to to me. but i linke your page an deffenetley the pic's thay are graid. PS: Sorry i can't write English verry well and good luck with your website.

6/13/2006 1:17 PM  
Anonymous Anonymous said...

Anyone knows how to do this with Gimp? It doesn't seem to have a fill mode called "Luminosity". There is a workaround by using a 50% fill opacity, but the image looks quite different (although the illusion still works). But I would like to make the picture look exactly as in the tutorial.

6/14/2006 4:39 AM  
Anonymous Anonymous said...

When I first saw this, before the tutorial was posted, the method I used was:

[1] Create two identical layer copies.

[2] Convert the lower layer in the Z-order to Grayscale using Image->Adjustments->Desaturate.

[3] Convert the top layer to a colour negative (I used the Difference blending mode originally, then merged it with an underlying solid white layer, before I realised that there was an "Invert" adjustments option).

[4] Increase the saturation of the colour negative layer.

The reason I had to increase the colour saturation was because the image I used was that of a girl's face, and images with lots of pastel shades in them perform poorly in the illusion unless the colour negative image is greatly saturated to compensate. If the base image contains lots of strong primary or secondary colours, and little in the way of pastels, then the Sadowski Original Method works well. As do variations that don't involve heavily saturating the colour negative version of the image.

Pick an image with lots of pastels, and try the Sadoswki Original Method. The result looks washed out. Boost the saturation of the colour negative image and the resulting illusion returns with greater fidelity to the original.

Another point to remember is that images with very fine detail also work better if saturation is increased, especially if that fine detail involves a juxtaposition of pastels with primaries/secondaries. (For those unfamiliar with primary & secondary colours, these are, in Web RRGGBB notation: primary red: #FF0000, primary green: #00FF00, primary blue: #0000FF, secondary yellow: #FFFF00, secondary cyan: #00FFFF, secondary magenta: #FF00FF. Colours close to these values, or close to similar colours with lower luminosities, work best).

It would be interesting to see if more intensive selective editing of the false colour layer (i.e., ramping up the saturation of pastel areas only) would have an even better effect with regard to fidelity.

6/15/2006 12:31 PM  
Anonymous j2 said...

My eyes are idiot eyes. They don't like these illusions. :(

6/17/2006 2:43 AM  
Anonymous LowResAtari said...

Anybody maybe have a Macromedia Fireworks tutorial for this?

6/18/2006 7:43 PM  
Anonymous Jaxom said...

Hi,
I've got a colour vision anomaly. When I look at your castle illusion everything's ok but with the illusion used in your tutorial the cherry in the spoon appear to be grey for me. All the other thing are coloured. The cherry on the first picture - the one used to create the illusion - is red.

6/19/2006 2:34 AM  
Anonymous Anonymous said...

Step 4 makes the image entirely white. I am using Adobe PS CS2.

6/19/2006 10:56 AM  
Anonymous Anonymous said...

Nice one! will play with this little trick quite a bit methinks.

Good stuff.

6/19/2006 3:35 PM  
Blogger Julie Oakley said...

very clever - I may play around with it

6/20/2006 6:17 AM  
Blogger Jerry A. Greene said...

I made one and put it here:
http://jagmmp.com/illusion.html

Thanks for the tutorial.

6/20/2006 9:42 AM  
Anonymous Anonymous said...

I couldn't use the atn file...can u help me out..
Pls mail me on akshat_rathi@rediffmail.com

6/24/2006 10:04 PM  
Anonymous MrAnderson said...

Lot of thanks for the tutorial

Made my color illusion at http://www.mrandersonmd.com/?p=78

Greetings

6/25/2006 1:13 PM  
Blogger Andrew748 said...

good toy thanks :)

and thanks for the roll over link :D

7/02/2006 5:44 AM  
Anonymous Anonymous said...

I will give this a try ,I have p/shop,and am learning gifs..

age 68 cp for 18 mnth
enjoying

8/06/2006 1:42 AM  
Blogger armageden said...

HEY I NEED SOME HELP!! i just learned all this just now and i have the images made and everything and completely done with the adobe photoshop and image ready programs. now i need to know how to post it online. can anyone help me??

8/08/2006 1:49 PM  
Anonymous Anonymous said...

I would like to say that this is the coolest illusion I have seen to date.

9/12/2006 6:47 AM  
Blogger jtechnet said...

Nice one John.
Simple yet nice output outcome!

9/18/2006 12:51 AM  
Anonymous Anonymous said...

works so good if you can get the lazy eye effect goin'...

10/16/2006 6:56 PM  
Anonymous Regis said...

That's so damn cool !! Thanks a lot !

5/14/2007 6:15 AM  
Blogger dot_sent said...

One can get a really amazing effect by looking at the dot for around 30 seconds (as said), then turning eyes some centimeters away from dot, THEN taking a mouse cursor to the image and slowly move your eyes towards the dot - it looks like a grayscale image is getting colorful while you do that.
Thanks to the author - It's really great idea!

5/22/2007 1:36 PM  
Anonymous Anonymous said...

This is so cool! I used PSP instead, but it's almost the same. Thanks for a nice tutorial!

6/19/2007 7:57 AM  
Anonymous Anonymous said...

great! ... but ... if you wanted to see the picture in colour, why desaturate it in the first place ;P

7/30/2007 12:51 PM  
Blogger Juan Jose said...

Hi

Its a wonderful illusion. I would like to know if someone can help me achieve this with Paint.Net.

Thanks

12/16/2007 10:46 AM  
Anonymous Anonymous said...

nicepost

2/12/2008 6:57 AM  
Anonymous Anonymous said...

Silly penis!

2/25/2008 8:07 AM  
Anonymous Rajita - Logo Design said...

Excellent Work

7/30/2008 12:37 AM  

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