Olympus-OM
[Top] [All Lists]

Re: [OM] Feeding the rumor mill

Subject: Re: [OM] Feeding the rumor mill
From: Ken Norton <ken@xxxxxxxxxxx>
Date: Wed, 8 Sep 2010 23:50:56 -0500
Here you go, Chuck.

http://zone-10.com/cmsm/index.php?option=com_content&task=view&id=538&Itemid=1

AG

> I have no idea how to create a custom fill or brush in PhotoShop to do
> what you describe but the image size you define for a 5D is
> approximately the same as I'd see 1:1 on my screen.  Tomorrow maybe I'll
> try to do a proportionally sized print of a small cropped section.
> On 9/8/2010 5:49 PM, Ken Norton wrote:
>> Well, I've devised a little test. Create an image file--doesn't have
>> to be big at all because we're just experimenting around and the
>> output can be rather tiny. Create this image file of, say, 300x300
>> pixels. Now create a custom fill or brush with alternating black and
>> white lines. These lines are one pixel in width.  Follow so far? While
>> you are at it, you might as well create a few other squares like this
>> with other colors.
>>
>> What you now have is one or more squares made up of white/black
>> one-pixel lines. At 100% on screen they should be perfecty
>> sharp-edged.
>>
>> Now print this at 300 ppi. Examine the print and tell me if you can
>> make out the lines. Change resolution to 240 ppi. See the lines?  Keep
>> going down until you can make out the lines. Now tell me again that
>> you NEED 300 ppi resolution from camera to printer. Most
>> printers/inks/papers won't even SUPPORT 300 PPI resolution as there is
>> too much bleed.
>>
>> In the film days you could figure a reasonable enlargement of 8x
>> before the image resolution started dropping to the point where
>> golden-eyes could see the difference. So, if you figure that a 300ppi
>> print is equivalent to a "contact negative", you should be able to use
>> a quality scaling tool to upres the photo to the equivalent to 8x
>> before the image is hashed up enough to be problematic. But other than
>> Genuine Fractiles, most scaling tools aren't anywhere near as good as
>> optical enlargement, so chop that 8x in half. 4X is a nice round
>> number. And amazingly enough, in my own tests, I've found that 4X
>> enlargement from digital files (considering that 300ppi is equivalent
>> to a contact negative) seems to be the point where my own eyes detect
>> the resolution loss.
>>
>> Saying the above paragraph another way... Take your image file and
>> uprez it 4x. Now when you print this at 300ppi, you're at the
>> threshold where print quality, according to those with perfect vision
>> will suffer. 8x uprezing is still fine for most general-purpose
>> applications.
>>
>> To bring this full circle, the 5D, when using the 4X factor, allows
>> for a print 38.8 inches in height. Inotherwords, you can make a 40x60"
>> print that is essentially perfect to everybody except those with
>> magnifying glasses.
>>
>> The 5D's native image height is 2912 which at 300ppi is the equivalent
>> to a contact negative print 10x15" in size.  This is why digital has
>> passed film in the EFFECTIVE resolution department years ago. Because
>> it isn't the capture side that is the limiting factor of output
>> resolution, but it's the output side that is the limiting factor of
>> output resolution.
>>
>> Back in the film days there were two reasons to shoot larger formats:
>> enlargement and tonal smoothness. With the 5D, the native non-enlarged
>> size is already almost 10x15" and tonalities is a non-issue as it
>> doesn't change regardless of how big or small you make the print.
>>
>> AG (do the test, I dare you) Schnozz
> --
> _________________________________________________________________
> Options: http://lists.thomasclausen.net/mailman/listinfo/olympus
> Archives: http://lists.thomasclausen.net/mailman/private/olympus/
> Themed Olympus Photo Exhibition: http://www.tope.nl/
>
>



-- 
Ken Norton
ken@xxxxxxxxxxx
http://www.zone-10.com
-- 
_________________________________________________________________
Options: http://lists.thomasclausen.net/mailman/listinfo/olympus
Archives: http://lists.thomasclausen.net/mailman/private/olympus/
Themed Olympus Photo Exhibition: http://www.tope.nl/

<Prev in Thread] Current Thread [Next in Thread>
Sponsored by Tako
Impressum | Datenschutz