17th September 2003, 12:33 PM
If your sample slide is properly exposed and you did not see any sign of grain on a 4X loupe. Use it for this experiment.
Scan the Slide and increase the resolution for the scan till you can view the grain clearly on you monitor screen in "Actual Pixels" setting (PS) .
You have already hit the resolving ability of the film, there are already no more detail available for the image except the film's grain structure. At this point, if you increase the scanning resolution, you are only scaning for the grain.
17th September 2003, 12:55 PM
yep thats right. but how will scanning make the grain BIGGER? i will get clearer but not bigger right? grain has got fixed size given the type of film and processing...
sorry, im connfused by what you are saying.
17th September 2003, 01:16 PM
If you always view the scanned image with "Actual Pixels" view Setting on PS. When the file resolution increased, the image actually magnify on your monitor screen. Therefore you'll always see the grain growing bigger and bigger on your screen if you increase and increase your scanning resolution.
Originally Posted by showtime
17th September 2003, 02:19 PM
the grain seems to be growing because when you scan higher res, there are more pixels in the image. thus when viewing actual pixel mode on PS, the area covered on the screen is a smaller (more zoomed) area. thus the grain is more magnified (due to the zooming of PS).. you will see that the percentage view indicated on the picture. like 12% or whatever...
on checking with the ruler on photoshop, the grain size is exacly the same. because of the scale, it appears to the eye as bigger...
im clear about this issue now...
31st March 2004, 06:30 PM
sorry for digging up an old post.
just like to ask, anyone tried comparing 10mp scans from consumer film scanners and compare them to scans at 2.1mp from those labs.
i have tried scanning at labs, resolution is roughly 1800x1200, enough to print 8r, but when i go to photoshop and view it at actual size, the photo looks grainy, esp at darker areas. that's with protra 400vc.
anyone tried scanning iso400 film at 10mp? do u get the same thing i'm getting?
1st April 2004, 09:49 PM
I have not done any practical comparo, but based on theory compare this:
1 A low resolution scan of a film, like those done by minilabs, at say 1000x1500 or 1.5Mp, in which each and every pixel consist of a real pixel scanned separately for the 3 primary colours.
2 A dSLR file at 2000x3000 or 6Mp, in which the pixels are arranged in RGBGRG......, and then interpolated, so, it is not genuinely 6Mp, except for the Sigma sensor.
So, I suppose that in terms of details, resolution or MTF, these 2 might be closely matched. As I say this is purely speculative.