Enlarging images...

[123456789]

I was wondering if anyone out there knew of a way to enlarge an image to about double its original size with a minimal loss of quality and minimal pixelation. Tall order, I know, but I need to put someone's head on a movie poster and if I simply shrink the poster, it'll print about 4" x 6" whereas I would ideally like 8 1/2" x 11". I could fudge it with layer styles and filters, but I'd rather not. I've played with such things as high pass filter, sharpen, resolution, etc. but haven't yet found the right combination. Can anyone help?
AdvTHANKSance. :)

[Scott]

There's actually no way to enlarge a raster image and retain the original quality. None.

There are plug ins such as Genuine Fractals Pro or Smart Pixel which claim to allow you to enlarge but even these packages are only decent at around a 130% enlargement, not a 200%.

[123456789]

Thanks. Perhaps one of these programs, some fudging and some painting around the edges, then. Might that make it look acceptable? I could print at 6" x 9" (which I guess would do.) Would it be worth the time IYO?

[Chris49]

From what I have learnd If you enlarge by a factor that is a whole number you will see the best results. for example 100x150 to 200x300

he next best option is to enlarge by a common factor. So going from 100x150 to 124x186 would work well

And you didn't think you would not need math in graphic design

[Dave]

and remember doubling the dimensions is a lot more than doubling the size! Increasing a 6x4 image to 12x8 changes the number of pixels by a factor of 4 not 2

[Scott]

Uhm.... no it doesn't change the number of pixels, that's where quality degrades.

[123456789]

This is where I've gotten to so far. As you can see, the head is quite rough. I tried the diffuse filter but it looked very 'smudgy' and so I brought it back to this.
http://groups.msn.com/_Secure/0TACRAn0Wx18lSeCLgGXnhdbhL!uKZS5BYsNbBSR5QlZP0CoU*4oWHHh0ByJn3bBaKvvXV0XArMC2llfDIcV1KZa*2ge*I7dQobM5LE1IiLjNych5zOMV6g/LVMatrix800x1096jpeg.jpg?dc=4675516027040460367

[123456789]

Somebody was nice enough to give me this piece of advice and I just thought I would share it:
-First, double the size of the image, making sure that you have the resample option checked and set to bicubic.
-Second, run a despeckle filter. Filter -- Noise -- Despeckle
-Third, double the size of the image again (with resample and bicubic selected)
-Fourth, run the diffuse filter. Filter -- Stylize -- Diffuse. Select Anisotropic as the method.
-Fifth, reduce the size of the image by half, so that it is the size you want it. (with resample and bicubic selected)
-Sixth, run the unsharp mask filter. Filter -- Sharpen -- Unsharp Mask. Set the radius and threshold to 2 or so and the amount to less than 100%. You can play around with it to see what looks good.

Play with the last step because depending on the image, the radius and threshold values will do a lot to bring out the contrast, hues, and spotty brightness of that image.

[123456789]

The results are in. I lined up 5 copies of the same image which I had resized different ways. (I cannot, unfortunately, show the results as I have been asked by the person whose face was the object not to do so.)
-In 5th place (quality-wise) was the original at 200% zoom
It was very, very pixelated.
-3rd place was a tie between the PS Elements resize wizard (found in the PS help menu) at 200% and just doubling the image size.
Both were very blurry and blotchy.
-2nd place (debatable) was the image scaled with 'Genuine Fractals' to 200%.
It was basically the same as the two tied for 4th, and seemed more pixelated at the edges but no less blurry. The edges were a little sharper. This may or may not be better depending on the usage. It was hardly noticeable, though.
-The best result was definitely achieved using the technique given to me by someone going by the s/n of Festivus. Thank you Festivus. This technique is the one I listed below. I haven't tried combining the 'Genuine Fractals' image with Festivus' technique simply because I don't think it would make that much difference to the final result based on my little experiment in re-sizing. 'Extensis Smartscale' is a program which claims 1600% scaling with no appreciable loss of image quality (?) but I haven't tried it.
I would like to re-iterate saying that the despeckle/diffuse/unsharp mask combo made an enormous difference in the quality of the re-sized image and would heartily recommend trying it if you have a spare moment (it takes about 2 minutes) and a source pic which is just a bit too small. I hope this can help someone. :)

[down2earth2]

[QUOTE=123456789]I was wondering if anyone out there knew of a way to enlarge an image to about double its original size with a minimal loss of quality and minimal pixelation:)[/QUOTE]

I knew I read an answer to this somewhere, and finally found it today. This is from the Photoshop CS Book for Digital Photographers, by Scott Kelby.

"Go under the Image menu and chose Image Size. Make sure Resample Image is turned on, Change Resample Image Interolation Method to Bicubic Smoother. Switch unit of measurement pop-ups menu from inches to percent and type in 110 which increases your image by 10%. Believe it or not, when you increase your image in 10% increments, or some reasons it doesn't seem to soften or blur the image. It's freaky, I know, but to believe it, you just have to try it yourself."

[PDG]

Ahh...good ole extravagant Scott Kelby. He reminds me of that chef, Emeril. 'BAM!'

Anyways, that method sorta-kinda works. If you do a search, you can also find an action to make the process simpler and faster.

Fact is, even if it's only enlarging by 10% at a time, there will come a time when PS needs to start 'guessing' where pixels go. It's this guessing game that causes distortion since PS simply wasn't created with this function in mind. In the printing industry this is pretty common knowledge. If you were to consult a professional printing company that specializes in enlargements, they will tell you exactly what Jolt did in his first reply. These same printing companies also happen to use the exact same programs mentioned.

If you do give Kelby's method a try please let us know hot it goes. I've yet to hear an actual testimonial about it.

[123456789]

bicubic 10% enlargement (http://www.wfu.edu/users/bennettk/upres.html)
I found this on the subject, looks good.
The difference between using the 'Genuine Fractals' and the method I mentioned below depends greatly on the source image. Mine was blurry and pixelated to start with and I got better results because the diffuse step helped clean up the image quite a bit. When using excellent high-res images, I've found that 'Genuine Fractals' does produce better results.