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Moondoggie Graphics
Posts: 3
How can I control the output size of a filter? For example, in FF stand alone I rendered a 20"x30" 300dpi jpeg image (9000x6000 pixel )... after 10 hours (yes 10 hours later!) it created a 125"x83" 72 dpi jpeg image. (When I try to do likewise in FF as a PS plugin and tell it to apply new layer my computer tries to render the image but eventually becomes non-responsive.) Any suggestions?
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Kraellin
Kraellin

Posts: 12749
Filters: 99
the output size of a filter is determined by the input size of an image. the default size of the life preserver image is 600 pixels by 600 pixels. if you input an external image to replace the default life preserver, then the external image size will be the output size of your render. even if you're just doing textures, the output size is still determined by the default image or file > new image or file > open image. there is ALWAYS an image loaded somewhere and that image ALWAYS determines the output size. so, you would have had to either loaded a 9000 x 6000 pixel image into FF or you used file > new image and set the dimensions at 9000 x 6000.

and since 125" x 83" at 72 dpi is the same as 30" x 20" at 300 dpi, i dont really see the problem, since photoshop or any other decent graphic editor really only looks at the dpi (ppi (pixels per inch))numbers. a bit odd, though. your output size SHOULD be the same as your input size.

the 10 hours is a bit of a concern, though. i've never had one take more than about 15 or 20 minutes, but again, i'm not working with those sizes that you are. but, that would be very dependent on the filter itself, as well as the input image size.

might i ask what you need such a huge size for, not that it's particularly pertinent here. just curious.
If wishes were horses... there'd be a whole lot of horse crap to clean up!

Craig
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Sign Guy
Digital Art Developer-Publisher

Posts: 554
Craig is correct as to the PPI vs. DPI. To set it to your original size in Photoshop, just

• Click on Image > Image Size
• Uncheck the Resample Image checkbox
• Change Resolution from 72 to 300
• Click on OK

Rendering times vary with the speed of your computer, the operating system, the filter and the size of the rendering. I regularly create tiles measuring 3600 x 3600 pixels using a quadcore PC running in Windows XP Pro and experience render times ranging from 15 minutes to a little over an hour. That's an area of 12,960,000 pixels or just under 13 megapixels. Your 20" x 30" is 6,000 x 9,000 pixels or a total area of 54,000,000 pixels (54 megapixels).

Your 54 megapixel rendering is 4.17 times larger than the image I typically render and should, therefore, take 4.17 times longer. For it to take over ten hours, however, would indicate a much slower machine and/or a very slow filter being used.

Fred Weiss
Allied Computer Graphics, Inc.
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Moondoggie Graphics
Posts: 3
Thanks for the feedback. I am still new at this dpi/ppi stuff. All I know is the professional processing lab which prints my images needs at least 250dpi. I have found using 300dpi seems to produce best results as I also downrez these images to 10x15 and uprez to 40x60. This may not be the average use (9000x6000 @300dpi) of FF as my business requires large format printing of photographs for commercial purposes. The smaller sizes I sell to individuals for home or office.

In any event I usually use the FF PS plugin method and the size into FF is the same size back out into PS but when it " no longer responds" I try it in FF stand alone. I have a old system 1.4ghz processor with 1.5mb ram and I usually have 8-10mb free disk space on my drive .. I am surprised it works at all! My disk drive is probably slow so all that adds up. The average rendering time for most filters is 30 mins to an hour but the really complex filters can take several hours - I'm retired so I can find other things to do while I wait.

Any other suggestions would be welcome.

Thanks
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Sign Guy
Digital Art Developer-Publisher

Posts: 554
PPI and DPI are very similar and often confused. PPI refers to the pixels per inch of a digital image and DPI refers to the dots per inch of print resolution of your output.

When working with the original image in Photoshop, what you are really interested in is the overall size or "pixel dimensions" of the image because it establishes the quality of the original image. The resolution of the source image, only tells you the quality at any given size. For example, a 300 x 300 pixel image (PPI) equals one inch of print size at 300 DPI. The same image equals three inches at 100 DPI and 4.17" at 72 DPI.

Your printer is telling you his specs at the size you want the image printed when he tells you 250 DPI. So if you want a 10" x 20" print, he is telling you that the source image should be 2500 x 5000 pixels in size and that you should set the resolution in Photoshop to 250 DPI. When he RIPs your file, he will be reprocessing your source image into an output file at the desired resolution for the print which is usually a higher number like 720 x 720 or 1440 x 1440 DPI. The quality (pixel dimensions) of your source image will govern how good the printer's results will be.

I would caution you that "upsizing" your source image is not something you should do as a normal procedure. The reason being is that you are creating new image information through interpretation of the existing information contained in your image. The distortions and pixelation that result can be anywhere from minor to major. To the greatest extent possible, you should try to work with large image sizes and only scale down.

You can dramatically improve on the render times in Filter Forge/Photoshop if you will add a blank hard drive to your computer and then designate it as a scratch disk in Photoshop. An 80 GB IDE drive at Newegg.com is typically around $38 plus shipping.
Fred Weiss
Allied Computer Graphics, Inc.
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Kraellin
Kraellin

Posts: 12749
Filters: 99
Quote
The reason being is that you are creating new image information through interpretation of the existing information contained in your image.


this is called interpolation. it means adding pixels to existing image to make the image larger. there are software programs that do this with very little loss of resolution. i dont recall any names right offhand, but they exist and you can google it. photoshop and paint shop pro will do this also, and their methods (normally bicubic) are pretty good up to a point. but if you're really increasing by a lot, then you shld look into a good size increase software.

and just to further confuse you, if you always think in pixels, you're generally going to be better off. i know a lot of folks try to work in inches and then convert using resolution and ppi/dpi, but it's much easier if you just think in pixels, because ALL of the other ways basically end up computing down to pixels. think of resolution as a multiplier. a 4" x 6" print at 300 ppi actually 1200 x 1800 pixels. when working on the web inches is pretty irrelevant. we only care about pixels. when printing, inches becomes more important, but you've still got to contend with that multiplier, resolution. so, inches times resolution = pixels. and that's true whether it's print (dpi) or screen (ppi).

also, you can help your cause like fred said with a new workspace harddrive, but i'd SERIOUSLY consider upgrading my entire system. 8-10 megs of free space is seriously inadequate for most professional work, especially if you're doing 9000 x 6000 prints!!! SERIOUSLY! 1.5 megs of ram is half of what you shld have. and a 1.4 ghz cpu is about the minimum possible to run some software out today. for the kind of processing you're doing (or trying to do), you'd be MUCH better off with a quad core, 3.ghz cpu, 3 gigs of ram and a nice half a terrabyte drive with a LARGE virtual ram space and a large dedicated partition for a photoshop workspace. i dont know your current financial situation and what i just spelled out might sound like a lot of $$$, but i'd guess you could come close for as little as $500 (with sales and rebates) and be MUCH happier with the speeds you'd get. 10 hours for a single render would just drive me nuts smile:)
If wishes were horses... there'd be a whole lot of horse crap to clean up!

Craig
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Sign Guy
Digital Art Developer-Publisher

Posts: 554
Here's some links to enlargement software:

PhotoZoom

Genuine Fractals

BlowUp

Fred Weiss
Allied Computer Graphics, Inc.
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Moondoggie Graphics
Posts: 3
Thanks so very much for the suggestions. I have Genuine Fractals on my shopping list. Christmas is just around the corner but my better half says I have to get rid of my other three old computer systems before another child comes a'courtin' ... I still have in the basement a 6400 x 200 Mac with 64 mb ram which is usable!

I have been pleasently suprised at the printed images at 20"x30" @300dpi. I have noticed though that the final product does tend to smooth out some of the detail.
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