Ah, I hadn't noticed those central areas before. I had been
concentrating on the edges where some cilia (?) are out of focus or
perhaps motion blurred (upper center image 1) or where there are
artifacts (lower left image 1).
In thinking about whether these things are visible in a given print size
I'm wondering if Bruce Fraser's rule-of-thumb sharpening rule might give
some guidance. His guidance on sharpening says to crop and resize the
image to the final size to be used for the print. Then display the
image at 25-30% on-screen while you do the sharpening and sharpen until
the image looks just very slightly crunchy.
The rationale for this 25-30% rule is that it's a rough representation
of the ratio between the resolution of pixels on screen and dpi in the
finished print. For example, if your computer screen has 90 ppi and
your finished print will be 300 dpi then 90/300 = 0.3 or 30%. That
takes care of the relative viewing sizes. The "slightly crunchy" bit
has to do with a slight softening effect of the paper print. That
slight crunchiness you built into the image will dissolve away on paper.
I suspect that, if you follow this sharpening rule and can't see the
slightly OOF areas or remaining artifacts at 30% of the finished print
size then you won't see them on paper either.
As a final test before committing to a huge print you can make a 5x7 or
8x10 of a cropped section of the large print that contains one of the
suspect areas.
Chuck Norcutt
On 9/4/2011 12:59 AM, Moose wrote:
> On 9/2/2011 3:29 PM, usher99@xxxxxxx wrote:
>> I hope Chuck is correct. My wife's identical twin was smitten by a
>> couple of the orchid shots and want them for her office.
>
> Here's what I am talking about.
> <http://galleries.moosemystic.net/MooseFoto/index.php?gallery=Others/MikeG/Flowers_and_Butterflies&image=Orchid-stackcombined8-14_FP.jpg>
> And
> <http://galleries.moosemystic.net/MooseFoto/index.php?gallery=Others/MikeG/Flowers_and_Butterflies&image=Paphgreenstackfinal_FP.jpg>
>
> I think the focus banding is fairly easy to see, both in the body and in the
> hairs on the edge of the green Paph.
>
>> I'll have to contact THE MAN for prints 'round here, i.e Bob, if he
>> thinks they will print OK. I can restack with the sharpening turned all
>> the way off.
>
> Sharpening does tend to only effect areas already somewhat sharp. So
> restacking without sharpening might well even it
> up. As to whether anyone but the ol' eagle eye* would notice in a print
> depends on how big a print. Unfortunately, I
> don't know. Maybe Bob will be able to guide you.
>
>> ...
>> The stacked images can take on an analytical feel, but I hoped the nice
>> backgrounds softened that. It is just one technique to use on occasion.
>> The nice detail in the orchids just seemed to tell me to try this
>> approach.
>>
>> Hey, the Moose and Carol Ann will be in the area??
>
> Goin' East Moose
>
> * Sheesh, what a troublemaker.
--
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