Got a print of the image. Cost me 50/- per sq. ft. [That's without the lamination, otherwise it's 60/-]. So 300/- for the 24x36 in. poster.
While there's enough detail [for instance, the texture on her lips & jacket is very good], overall, the print is not exactly the same as the original image as viewed on the screen.
Basically, the details/lighter shades in the shadowed/dark areas don't seem to come through [that's the best description I can think of]. For instance, her hand is hardly visible in the print.
The explanation I was given is that the image on an LCD is always brighter than the print. To test this out, I got a few 4x6 prints of the same image from snapfish at different levels of brightness [as tweaked in photoshop]. The snapfish prints are much more accurate & very close to the actual image [as viewed on my screen]. Though, the image on screen still seems a bit warmer, [for instance, her hair seems much redder (sic)] it could well be a calibration issue. Also, the variance in brightness does not affect the prints as much as it does on screen. The step up from 20% to 30% to 40% is much more obvious in the latter scenario.
So all in all, if snapfish uses the same method/printer to print out large prints as well, the results will be much more accurate & satisfying. Now, snapfish charges a hefty premium. So I'd actually suggest trying out zoomin or itasveer [which are much cheaper], for similar needs/sizes. They ought to be comparable to snapfish, given that they too are online professional printing services. Or there is the local photographer [vs the local printer], of course. I don't have any 1st hand experience with either yet, though.
Again, the printout at the local printer [vs photographer] might not be a bad option, if the image is bright enough [i.e. not too many dark areas &/or high contrast]. But I still don't get what is exactly amiss. [For instance, the white lettering {release date} is very satisfactory]. So I may be way off the mark here.
BTW, I never really got a chance to check out Landmark. I assume they will have a good enough collection, especially at Phoenix Mills, Mumbai.
& many thanks to all those who helped. Much appreciated!
{Note: The image from the camera makes the poster look much brighter than it actually is; & the whole pic is much yellower (sic) than it actually is}
Here's the original image -