rez up?

Archived from groups: rec.photo.digital (More info?)

What do you mean when you say, "By one step"?
Depending on how critical you are, I'd say that you can safely rez up a
4MP .jpg file to a 5 MP .jpg file.
Since an image in RAW carries more info than the same image in .jpg,
I'd assume that it could safely tolerate a little more rezzing than a
jpg. The degree of safe rezzing that can be done depends entirely on how
critical you are of image quality. Are you an eyeball guy or a
magnifying glass guy?
Bob Williams

pshaw@emmet.com wrote:
> in some text/lesson i read that one can safely (and effectively) rez
> up (by one step) raw photos in photoshop ... any comments yay or nay?
>
> tia .... steve

Archived from groups: rec.photo.digital (More info?)

>From: pshaw@emmet.com

>in some text/lesson i read that one can safely (and effectively) rez
>up (by one step) raw photos in photoshop ... any comments yay or nay?

I do it all the time with digital files, rezzing 8 Mpixel files to print 360
ppi @ 16x24" (ie, 23.2 MB files -> 143 MB files) ... the native file is 146 ppi
at this print size so this is almost a 250% linear increase ... if the original
image is good enough I get better large prints doing this than I do from 35 mm
film.

Some tips ...

* if you have Photoshop CS use the 'bicubic smoother' option if doing it in one
step, or use 'bicubic' in 110% steps if you don't have CS. This describes the
110% method well (so-called 'stair interpolation') ...
http://www.fredmiranda.com/SI/

* Canon recommends a small bit of USM on the original image to correct for
softening via the AA filter. They recommend 300%, .3 radius, 0 threshold but I
think it's wise to make a copy of the original and resize it both ways (ie,
without this initial USM and with it). Then resharpen to taste on the final
resized image. Be careful not to oversharpen the final file.

* shoot raw mode and use the best raw converter you can find since the best
ones have a smoother de-mosiacing algorithm and the enlarged image looks better
(smoother) when the original has fewer de-mosiacing artifacts. I've tried four
converters and think Phase One Capture One does the best job.

I'm resizing to 360 ppi because that's the native rez of my printer but you can
probably do fine at 240 or 300 ppi with most printers.

Give it a try, you have nothing to lose

Bill

Archived from groups: rec.photo.digital (More info?)

bill ...thanks for the advice ...

indeed i'm talking about rez'ing up the raw file, not the stair
interpolation of tif's, either manually or with purchased software ...

i'm using a 20d to shoot my raw files ...so you think i could rez it
up one step in size and also to say 288 ppi? i know i know i need to
print some :-) ...

sorry but what is "usm"? and would that explanation tell me where i
input the threshold, radius etc values? -

yes, i'm using photoshop cs ...

i spoke to the nice folks at c1 and they're still not ready with
software for the canon 20d in the windows environment :-( ...

thanks again and i look forward to your explanation ...

steve


On 13 Dec 2004 17:13:03 GMT, bhilton665@aol.comedy (Bill Hilton)
wrote:

>>From: pshaw@emmet.com
>
>>in some text/lesson i read that one can safely (and effectively) rez
>>up (by one step) raw photos in photoshop ... any comments yay or nay?
>
>I do it all the time with digital files, rezzing 8 Mpixel files to print 360
>ppi @ 16x24" (ie, 23.2 MB files -> 143 MB files) ... the native file is 146 ppi
>at this print size so this is almost a 250% linear increase ... if the original
>image is good enough I get better large prints doing this than I do from 35 mm
>film.
>
>Some tips ...
>
>* if you have Photoshop CS use the 'bicubic smoother' option if doing it in one
>step, or use 'bicubic' in 110% steps if you don't have CS. This describes the
>110% method well (so-called 'stair interpolation') ...
>http://www.fredmiranda.com/SI/
>
>* Canon recommends a small bit of USM on the original image to correct for
>softening via the AA filter. They recommend 300%, .3 radius, 0 threshold but I
>think it's wise to make a copy of the original and resize it both ways (ie,
>without this initial USM and with it). Then resharpen to taste on the final
>resized image. Be careful not to oversharpen the final file.
>
>* shoot raw mode and use the best raw converter you can find since the best
>ones have a smoother de-mosiacing algorithm and the enlarged image looks better
>(smoother) when the original has fewer de-mosiacing artifacts. I've tried four
>converters and think Phase One Capture One does the best job.
>
>I'm resizing to 360 ppi because that's the native rez of my printer but you can
>probably do fine at 240 or 300 ppi with most printers.
>
>Give it a try, you have nothing to lose
>
>Bill

Archived from groups: rec.photo.digital (More info?)

bill .... that covers it all perfectly! thanks so much ...next book on
my 'must read' list is fraser's

thanks again for the time and excellent explanations ...

steve

On 14 Dec 2004 16:58:52 GMT, bhilton665@aol.comedy (Bill Hilton)
wrote:

>>From: pshaw@emmet.com
>
>>indeed i'm talking about rez'ing up the raw file, not the stair
>>interpolation of tif's, either manually or with purchased software
>
>Ah, I see now ... you're talking about the CS Raw converter with the option and
>the 'size' box where you can bump it up a step to say '4096 x 2731' (one of
>the options for my 8 Mpix 1D Mark II so I assume you have a similar option with
>the 20D), right?
>
>I've never used that feature but I'm reading Bruce Fraser's fine book "Camera
>Raw with Photoshop CS" and he recommends using this RAW resizing when you need
>to process a number of files smaller (say for jpegs for the web), but for
>upsampling he feels it's pretty much a wash whether you do it here in the RAW
>converter or later with Image > Image Size (though he does it later himself,
>preferring to resize after he's done the basic digital work on a smaller
>image). This is on pg 73 if you get a chance to look at the book, say in a
>bookstore.
>
>Personally I'd convert a couple of files normally without resampling and do the
>resampling with Image Size to the same dimensions as the fixed sizes allow and
>save them with a new name, then reconvert the same raw files but this time do
>the resampling in the RAW converter and see if there was a big difference when
>comparing the two files. This will probably answer your question quickly.
>
>>i'm using a 20d to shoot my raw files ...so you think i could rez it
>>up one step in size and also to say 288 ppi?
>
>The 288 ppi is meaningless until you get ready to print, it's just a
>convenience to change it in the converter. That is, if you pick the upsample
>option to say 4096 x 2731 you can put any number you want in the 'resolution'
>box and all it does is fill in a field in the file header, the file will still
>be the same dimensions. It's in the RAW converter so you don't have to open
>Image > Image Size to change it if you don't want to but it doesn't mean
>anything until you actually go to print. So yes, you set it to 288 ppi without
>affecting anything else.
>
>>sorry but what is "usm"? and would that explanation tell me where i
>>input the threshold, radius etc values? - yes, i'm using photoshop cs ...
>
>Ah, this is not in the RAW converter (now I see better what you were trying to
>do) ... "USM" stands for Unsharp Mask, you access it from the main menu bar at
>Filter > Sharpen > Unsharp Mask ... Canon recommends a quick shot of USM at amt
>300, radius 0.3 and threshold 0 to counteract the slight blur of the AA filter.
> Once you're ready to print you should run USM more aggressively (with higher
>radius) to taste ... sharpening is a whole 'nother topic, with literally dozens
>of ways to do it.
>
>>i spoke to the nice folks at c1 and they're still not ready with
>>software for the canon 20d in the windows environment :-(
>
>Ah yeah, I heard mid-December but they've missed deadlines before The
>Photoshop RAW converter is still better than the Canon one though ... if you
>really want to learn well it I'd recommend the Fraser book mentioned above.
>
>>thanks again and i look forward to your explanation ...
>
>Hope this helps.
>
>Bill