16bit, colorspace-1, size-1 -> 8bit, colorspace-2, size-2

deejjjaaaa · 10-09-2007, 07:09 AM

Hi,

what will be your sequence of actions in Adobe Photoshop to convert
an image (16 bit, colorspace-1, X1 pixels by Y1 pixels) into 8 bit, colorspace-2, X2 pixels by Y2 pixels... colospace-1 = ~prophoto, colorspace-2 = ~srgb, X1Y1 (6-12 Mp) >> X2Y2 (1-3 Mp)

1) 16bit->8bit, colorspace-1 -> colorspace-2, X1Y1 -> X2Y2

2) 16bit->8bit, X1Y1 -> X2Y2, colorspace-1 -> colorspace-2

3) colorspace-1 -> colorspace-2, 16bit->8bit, X1Y1 -> X2Y2

4) colorspace-1 -> colorspace-2, X1Y1 -> X2Y2, 16bit->8bit

5) X1Y1 -> X2Y2, colorspace-1 -> colorspace-2, 16bit->8bit

6) X1Y1 -> X2Y2, 16bit->8bit, colorspace-1 -> colorspace-2

7) does not matter for 99.99% of population

And why ?

Thank you...

blende8 · 10-09-2007, 07:47 AM

Why would you change colorspace???
Re-sizing always at the end.

shutterdrone · 10-09-2007, 07:50 AM

I always do bit reduction (16b->8b) last. Do any re-sizing right before that.

Why?

Because reducing bit-space before doing other operations can reduce the detail adjusted in those operations (i.e. less actual detail ends up being no information); I'm not sure the sizing matters, I just prefer to do any operations on as high of a resolution image as possible. (In fact, my last steps in producing an image for print or some other media are, exactly: change size, convert to b&w [if doing b&w images for web- i always work and print them in color mode], and then reduce to 8bit.)

!c

ochoto · 10-09-2007, 07:55 AM

I would take number 5 since you mantain higher precision and wider colourspace through transformations but IANAE (i am not an expert

. Interesting question in any case.

10-09-2007, 07:09 AM	#1
deejjjaaaa Veteran Member Join Date: May 2007 Location: steel city / rust belt Posts: 2,043	16bit, colorspace-1, size-1 -> 8bit, colorspace-2, size-2 Hi, what will be your sequence of actions in Adobe Photoshop to convert an image (16 bit, colorspace-1, X1 pixels by Y1 pixels) into 8 bit, colorspace-2, X2 pixels by Y2 pixels... colospace-1 = ~prophoto, colorspace-2 = ~srgb, X1Y1 (6-12 Mp) >> X2Y2 (1-3 Mp) 1) 16bit->8bit, colorspace-1 -> colorspace-2, X1Y1 -> X2Y2 2) 16bit->8bit, X1Y1 -> X2Y2, colorspace-1 -> colorspace-2 3) colorspace-1 -> colorspace-2, 16bit->8bit, X1Y1 -> X2Y2 4) colorspace-1 -> colorspace-2, X1Y1 -> X2Y2, 16bit->8bit 5) X1Y1 -> X2Y2, colorspace-1 -> colorspace-2, 16bit->8bit 6) X1Y1 -> X2Y2, 16bit->8bit, colorspace-1 -> colorspace-2 7) does not matter for 99.99% of population And why ? Thank you...

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10-09-2007, 07:47 AM	#2
blende8 Veteran Member Join Date: Feb 2007 Location: Bremen, Germany Photos: Albums Posts: 1,521	Why would you change colorspace??? Re-sizing always at the end.

10-09-2007, 07:50 AM	#3
shutterdrone Forum Member Join Date: May 2007 Location: Houston Posts: 75	I always do bit reduction (16b->8b) last. Do any re-sizing right before that. Why? Because reducing bit-space before doing other operations can reduce the detail adjusted in those operations (i.e. less actual detail ends up being no information); I'm not sure the sizing matters, I just prefer to do any operations on as high of a resolution image as possible. (In fact, my last steps in producing an image for print or some other media are, exactly: change size, convert to b&w [if doing b&w images for web- i always work and print them in color mode], and then reduce to 8bit.) !c

10-09-2007, 07:55 AM	#4
ochoto New Member Join Date: Mar 2007 Location: Spain Posts: 6	I would take number 5 since you mantain higher precision and wider colourspace through transformations but IANAE (i am not an expert . Interesting question in any case.