Why do my skies appear grainy

MK
Posted By
Michael_Kitei
Jun 25, 2004
Views
454
Replies
18
Status
Closed
Using 7 and now CS with OS10.3.4, scanning at a high though not max res with my Nikon 8000 at superfine settings I still tend to see a disturning lack of smoothnes in flat areas of sky. I would say it looks grainy, even reticulated. I’m working from medium format tmax film which is extremely fine grained and sharpening the skies less than the rest of the picture to try to avoid this problem.

I just did a 20X30 light jet print from a digital file and was disappointed because of this granular appearance of the skies.

Any thoughts?

Mike

Must-have mockup pack for every graphic designer 🔥🔥🔥

Easy-to-use drag-n-drop Photoshop scene creator with more than 2800 items.

PF
Peter_Figen
Jun 25, 2004
Any area that is out of focus is always going to look grainer that in focus areas. Film processing, chemistry and exposure all affect perceived grain. Which medium format – 645, 6X6, 6X7 etc? 645 going to 20X30 would definitely have some visible grain. How old is the emulsion. The newest versions seem to be finer. Lastly, I would have someone who really understands scanning negs on a good drum scanner, scan it for a reference comparison. You might be surprised at what you find.
MK
Michael_Kitei
Jun 25, 2004
Newly purchased film shot on a 6X9 Horseman VHR field camera. I doubt that focus is the issue. In working the film I consciously darkened certain areas of sky to bring out some contrast. I did this by adding a layer of grey/softlight and painting black at an opacity of about 7%.

Mike
L
Larryr544
Jun 25, 2004
Don’t sharpen the sky at all. If need be gently blur the noise out of it.
BG
barry_gray
Jun 25, 2004
What am I missing here?
Play with the blue channel in the sky only?
PF
Peter_Figen
Jun 26, 2004
Michael,

I didm’t mean to say that focus might have been an issue, only that because skies often have very little or nothing in focus, what you do see is grain, not the detail that grain normally resolves. Because parts of the image with detail hide the effect of grain so well, areas like sky often look overly grainy by comparison. Anything you do to add contrast to part of the image will also tend to emphasize the grain.

What developer was used and was the film pushed at all? Is the exposure normal or perhaps a bit on the hot side?

There are grain/noise reduction software solutions out there that might help. I can’t think of them off the top of my head, but a place like luminous-landscape.com will have more information in their forums.
R
Ram
Jun 26, 2004
Try the demo version of Grain Surgery.

<http://www.visinf.com/>
MK
Michael_Kitei
Jun 26, 2004
original in tmax monochrome. How will working in Blue channel help? Please take your response a step further.

Mike
MK
Michael_Kitei
Jun 26, 2004
Thanks, I’ll look into this.

Mike
P
progress
Jun 26, 2004
Could resolution be the culprit here? I know that 35mm film can display grain if its scanned at high res close to its theoretical grain limits (ie pulling a 4000×3000 scan from a 35mm)…sharpening only worsens this effect. I also know that some medium formats have a film grain limit close to 35mm but offer a better quality because its a lower ratio compared to the overall image area. I think 2 1/4 is one of these formats, but im not sure about others.

I only discovered this years and years ago, because the client complained about "mildew" on the grass that he had scanned..it turned out that due to the crop he was sucking nearly 8000 pixels out from a 35mm and the "mildew" was in fact the surface grain of the tranny…oh how the conversation about right tools and materials for the right job was fun afterwards.
MK
Michael_Kitei
Jun 26, 2004
I could try scanning at a lower res. or down sampling. It does show up on the screen. Mike
P
progress
Jun 27, 2004
lower res scanning is the only way if you have picked up the grain, because its in the file, so downsampling will help a little but not remove it.
AS
Ann_Shelbourne
Jun 27, 2004
Look at each of your channels separately.

Is the "grain" worse in the Blue channel?
If so, you are almost certainly seeing Scanner "noise" rather than film-grain.

Blurring just the blue channel could help to give you smoother skies.
Z
Zeb
Jun 27, 2004
Tmax is a black and white film, why scan in colour?
MK
Michael_Kitei
Jun 27, 2004
I have been scanning in 16bit B&W.

Mike
RH
r_harvey
Jun 28, 2004
See posts #3 and #9.
AS
Ann_Shelbourne
Jun 28, 2004
I didn’t think that scanners scanned in "black and white".

Surely they scan using their R, G, and B-sensitive sensors and then use their own algorithm to determine the luminosity values needed to produce a black and white image?

I would scan in RGB and use Photoshop’s channel mixing to produce the optimum rendering — particularly if you are going to print from an RGB inkjet.

But look out for noise in the blue channel.
MK
Michael_Kitei
Jun 28, 2004
Nikon has the grayscale option and it’s a smaller file than the rgb.

Mike
PF
Peter_Figen
Jun 28, 2004
The big reason for scanning in RGB is that the collective noise in each channel is effectively averaged, eliminating much of it. I don’t know about the Nikon, but my Howtek offers Grayscale scanning using any one of the three PMTs. You still need to send RGB to a Lightjet no matter what, so in this case, it’s certainly not going to be a matter of file size.

MacBook Pro 16” Mockups 🔥

– in 4 materials (clay versions included)

– 12 scenes

– 48 MacBook Pro 16″ mockups

– 6000 x 4500 px

Related Discussion Topics

Nice and short text about related topics in discussion sections