Re: Ex-Sperry-ment #4: buttal and re-buttal . . .

Glenn Butcher Wrote:
--------------------------------------------------
> . . . I'm a fan of posting images sized appropriate
> to the rendition medium.  That way, I control the
> resizing operation, not some programmer who
> wrote the image tag code for the browser.  And,
> I always add just a scooch of sharpening to my
> resized images, for the reason I outline above.

Great minds (giving myself the benefit of a great deal of doubt) apparently really do think at least somewhat alike!  But IMHO once the NGDF has its say, the output is going to be a maximum of 1024 pixels wide, so the pair of screen shots of Photoshop or Lightroom or whatever at different sizes aren't reflective of the final rendition medium.

Glenn Butcher Wrote:
-------------------------------------------------------
> . . . to follow up, here are the two images, as
> rendered by {the} NGDF:
>
> 1. Full-sized, JPEG-compression: 40, Width: 4948 Height: 3280, Filesize: 808Kb

>
> 2. Small-sized JPEG-compression: 98, Width: 1024 Height: 678, FileSize 414Kb:

>
> So, my conclusion for NGDF posting would be to
> keep images full-resolution from the camera, but
> to JPEG-compress the bejesus out of them for
> posting . . .

As before, my tired old (nearly 4/5 of a century) eyes cannot detect any significant difference — not even in the fine screen of #463's cinder catcher.

John Bush Wrote:
-------------------------------------------------------
> All this tech stuff is beyond me but that is a
> very nice picture.

I heartily second that motion!!    

Glenn Butcher Wrote:
-------------------------------------------------------
> Thank you; 2015 Chama Steam Fall Classic,
> first runby of the triple-header, at Lobato.
>
> Edit: Looking at these renders, they're not
> the best I have of this image.  Should be a
> little darker . . .


IMHO, Glenn -

There's nothing to be gained by re-sizing partway down from the original scan or digital file, so use .jpg compression to get the file just small enough to be acceptable to the NGDF ( < 2.44 MB )   =OR=   re-size all the way down to 1024 wide by whatever high, apply a scooch of sharpening, and save at a bandwidth-saving compression that yields a file in the 250K range.  One extreme or the other, no wishy-washy halfway measures.  Just for giggles, here's a final comparison —

1.  Olaf's photo of Hillcrest #10 resized from 5120×3072 down to 2048×1365 pixels (200 dpi), which allows a fairly high .jpg quality setting of 94 to keep the size just below the 2.44 MB limit (actually 2.372 MB here):


2.  Example #4 from my previous post, which was re-sized to 1024×683 pixels, "unsharped" a scooch at 60%, r=1.5, t=2, and saved at a .jpg quality of only 50 to keep the file down to a storage- and upload-friendly size of about ¼ MB (actually 253K):


No question the photo would be a bit sharper if saved at a .jpg quality of 95 or even 70 instead of 50, but on a monitor – or especially a so-called "smart" phone – the resolution isn't there anyway.  And of course if you're making prints I assume you'll be using the original hi-res .tif to begin with . . .

- El Abuelo Histœrico, Greengo y Curmudgeoño de los Locomoturas Viejos y Verdes,
aka Der Grossväterlich DünkelOlivGrünDampfKesselMantelLiebHabender



Edited 1 time(s). Last edit at 04/25/2021 12:43PM by Russo Loco.