Author Topic: Artifacts & Noise... How much is too much? (Read 8780 times)

Cricket · « **on:** June 28, 2007, 06:26 »

Hi Guys,

Another newbie question here. I have been playing around with the noise ninja demo and I am thinking of buying it as it really does greatly clean up images. However when it comes to things like fine textures... it has a tendency to blur stuff.

Fortunately though, Noise Ninja has an undo brush where I can undo areas that get de-noised too much.

Anyway... the question is... how much noise is too much noise?

For example, I can still see what looks like noise artifacts in a photograph that I took which had a pine tree in it (fine texture).

However, if I de-noise the pine tree too much in an attempt to get rid of some the stray pixels that don't quite match the color of the rest of the pine tree, the tree's needles begin to look all smudgy.

So what do I do??

Leave that area of the photograph alone? And only de-noise areas where there is relatively uniform (or should be anyway) color (i.e. blue sky, etc) ?

I guess I am asking this question, because I-Stock seems totally obsessed with noise/artifacts compared to other places and that was the company who rejected me (see my previous post of "Compression Artifacts... How do I spot them?").

Anyway... any thoughts/advice you have on this matter would be greatly appreciated.

Thanks,

Cricket

leaf · « **Reply #1 on:** June 28, 2007, 07:13 »

yeah i would denoise the area that is flat and really needs it and leave the parts alone that have lots of detail.

If you buy the version of noise ninja that can be used inside of photoshop as a plug in, you can make an copy layer of your background and then use noise ninja on that. Then you can mask that layer to show or hide so you can put the noise reduction where you want it and have it 50% some areas and 25% other areas and full strength in other areas......

if that made sense.

hatman12 · « **Reply #2 on:** June 28, 2007, 11:37 »

What camera are you using Cricket?

It seems to me that you are trying to hide/mask/resolve a problem without first of all trying to get rid of the problem in the first place.

Noise and artifacts are usually created by incorrect exposure/camera settings/high ISO.

I assume you are using ISO 100 for everything stock related.

Next, turn off all the in-camera processing - sharpness, saturation etc.

Then, find out how to correctly expose for your camera. Learn how to 'shoot to the right' for those pictures with white highlights, and 'shoot to the left' for those with heavy shadows. Take a number of exposures and compare the results.

In 99% of cases, noise is a result of incorrect exposure. You might THINK you are exposing correctly, but you should go through a test procedure to make absolutely sure. You will be surprised by what you find out.

a.k.a.-tom · « **Reply #3 on:** June 28, 2007, 16:46 »

Amen, Hatman..... sound advice... unlike the old days when you had all the time in the world to play with your photos... if you want to make it in stock, you need to eliminate as much as possible, post-shoot work 'photoshoping'. There's no time for it.
I have totally changed the way I shoot now... doing all I can to get the best possible image out of the camera, rather than.... "oh, i'll just fix that later in photoshop". One can't be spending a half hour painting out this or that or denoising or making horizons straight, whatever.... just ain't no time, bro!
Of course, there will be those shots that you will want to make special, or, at the advice of a reviewer, you will have to tweak if you want them to accept it. After 45 years of shooting, believe it or not, selling in the micros has made me a better, more discriminant photog. I spend the extra seconds or minute at the shoot, saving who knows how long pounding on the keyboard and sliding the mouse until 1 in the morning. LOL

-tom

Cricket · « **Reply #4 on:** June 30, 2007, 21:33 »

Leaf,

Thanks for the advice. I think that I-stock is just getting incredibly picky, as the photographs that they rejected for artifacts and noise were accepted by the other agencies.

Anyway.... I have to wonder... is this artifact and noise thing that I-stock is obsessed with that big a deal?

I mean if I have to blow up the image to 400% to see it... is it really going to affect the quality of the image if it is used in a magazine, book or on a website?

I guess I can see it as a problem if the image was purchased with the intention of interpolating it to a larger size... then noise/artifacts might become an issue.... but I just don't see how artifacts which can only be seen at 400% can be an issue if the image is going to be printed out at 100% or less.

I guess I am venting about I-stock... but I would love to hear other's thoughts on this artifact thing.

Cricket

madelaide · « **Reply #5 on:** July 01, 2007, 13:22 »

I think sometimes the rejection reason is not correct. I had a couple of imags rejected some time ago for artifating, but they were natural speckles from reflection on a texture. Scout reverted the rejection.

I had two rejected yesterday for noise/artifacting, but I think it's the texture (rough paper) that is mistakenly being taken as noise. Another Scout ticket on its way. If only these reviews were faster...

Regards,
Adelaide

sharply_done · « **Reply #6 on:** July 01, 2007, 13:29 »

Quote from: madelaide on July 01, 2007, 13:22

I think sometimes the rejection reason is not correct.

I agree with this. I think that sometimes the image is just "off" (i.e. technically and/or conceptually marginal), and the reviewer selects one of the standard reasons to reject it. Maybe there needs to be a "meh" rejection reason.

hatman12 · « **Reply #7 on:** July 01, 2007, 13:58 »

Yes Tom I agree wholeheartedly.

However sometimes all the planning in the world doesn't allow for things not seen at the scene or not noticed at the time.

On Saturday I had a three hour studio session with a lovely girl, and I've got 37 'possibles' out of about 120 shots. That's great.

Now if only I had noticed that logo on her jeans..........

leaf · « **Reply #8 on:** July 01, 2007, 14:17 »

Quote from: hatman12 on June 28, 2007, 11:37

Next, turn off all the in-camera processing - sharpness, saturation etc.

or better yet, if you can - shoot in RAW

madelaide · « **Reply #9 on:** July 01, 2007, 18:30 »

Quote from: hatman12 on July 01, 2007, 13:58

Now if only I had noticed that logo on her jeans..........

BTW, the double stitch in the back pocket of Levis jeans is trademarked.

Regards,
Adelaide

Cricket · « **Reply #10 on:** July 01, 2007, 21:46 »

You know....

I'm curious about one thing... If you get rejected three times by I-stock are you permanently barred from ever trying again? Or do you have to wait a while?

Cricket

Grizzlybear · « **Reply #11 on:** July 03, 2007, 06:43 »

Hi,Too much noise is noise visible to the naked eye at 100%

If you use Noise ninja,grain surgery,or neat image,you will only degrade your images.

To avoid unacceptable noise,get your exposure right:

Exposure

Thanks to digital cameras, exposure has never been so easy and simple to achieve, for general outdoor photography. (Studio work still requires a hand-held meter and grey card for its more exacting demands on the photographer) Most of the time matrix (evaluative) metering, will do a great job. For portraiture, centre-weighted is preferred, and where high contrast separates dark from light, spot metering comes into its own. Considering stock photography, we need to also keep in mind the element of noise, the biggest reason for rejection in our business- noise can be reduced in post-processing, to an extent, but if we can avoid excessive noise when making our images, the better our chances of approval, and less time at the computer. Correct exposure is how to control noise at the making/taking stage- and correct exposure is simple-By studying the histogram on the camera’s monitor screen, we can adjust our exposure compensation to ensure that the bulk of the graph is just to the right of centre, and each end is just touching bottom corners.- If left-hand side of graph climbs left screen edge, the shot will be over-exposed, with no detail in the shadow areas: If the same thing happens to the right-hand side, highlights will be blown, rendering the shot totally useless. For a second opinion, we can use the highlight flashes, also on the monitor screen, which flash black and white when highlights are blown. NOTE: If you can, get hold of a hand-held exposure meter, and you will be amazed at the difference it will make to your images
Sometimes you will find a scene will be beyond the camera’s 5-stop dynamic range, so if you meter using ,Matrix (Evaluative) or Centre-weighted, you will lose some detail in either highlights or shadows. A split-graduated neutral density filter (ND Grad) is recommended, But if you don’t have one: Try Dynamic Range Increase: With camera on tripod: meter for highlight, take a shot-then meter for shadows, take another shot. In Photoshop, add lighter image to darker as a new layer, then: Select> Color Range-click highlights ,check “invert”, click “OK”. Add layer mask. Filter> Blur> Gaussian Blur 250 pixels. Flatten and save. You will get detail in highlights and shadows

To reduce noise in existing images:

- Noise
Image> Mode> LAB Colour> Channels
Channel “a” Gaussian blur drag radius slider until noise just starts to go - click “OK”
Channel “b” Ctrl+F
Channel “lightness” Filter> noise> despeckle
Image> Mode> RGB colour

Regards, Grizzlybear

Cricket · « **Reply #12 on:** July 07, 2007, 22:28 »

Hi Guys,

Okay this post is a take off from my earlier posts about noise and artifacting.

The question is how much artifacts and noise is too much for a picky place like I-stock?

The reason why I am asking is that some of the images I-stock rejected for "too much artifacting" the other places took without blinking an eye.

For example.. I have some pictures of people engaging in sports activities. These shots were taken outside on a clear, sunny morning.

With most stock agencies... all I need to do is de-noise the blue sky and I am done... however with I-stock... do I need to de noise every freakin' area of the image?

Like for example if the deep shadow areas of the image have slightly lighter shades of black speckles in them, do I need to touch those areas up too?

How about if there are a two or three stray speckles seen on a person's shirt or jacket?

Is Istock looking for a smooth plastic look to an image?

BTW... I am well aware that noise can be reduced (not eliminated but only reduced) with the proper exposure and all that... so please spare me the long winded replies about looking at my histogram, using a different camera and all that rot.

I mean lets face it folks... just like sh-t, NOISE happens!

So how much of it is too much for a place like I-stock??

Cricket

hatman12 · « **Reply #13 on:** July 07, 2007, 23:00 »

Istock won't accept anything where noise or artifacts are present IN ERROR, in other words where they could have been avoided.

However there are situations where noise is unavoidable, such as in sports arenas or shots taken at night; noise is part and parcel of this type of photography.

I have found that in the few occasions when I've had noise unavoidable but wanted to submit the image, an explanatory note to Inspector and Buyer usually does the trick.

Example here:

http://www.istockphoto.com/file_closeup.php?id=3704818

and here:

http://www.istockphoto.com/file_closeup.php?id=3085277

madelaide · « **Reply #14 on:** July 08, 2007, 15:11 »

Quote from: Cricket on July 07, 2007, 22:28

Like for example if the deep shadow areas of the image have slightly lighter shades of black speckles in them, do I need to touch those areas up too?

There were occasions in which there was some noise caused by overedition - often in an underexposed image, even if just slightly, that I lightened up and shaded areas particular suffer more. I think sometimes they exagerate in the importance of those small areas, but anyway, technically they are correct.

I try to check possible problematic areas and denoise or blur them slightly to get rid of any noise pattern.

Regards,
Adelaide

a.k.a.-tom · « **Reply #15 on:** July 10, 2007, 18:49 »

Quote from: Cricket on June 30, 2007, 21:33

I mean if I have to blow up the image to 400% to see it... is it really going to affect the quality of the image if it is used in a magazine, book or on a website?

I sure see your point, Cricket. I've been down that very road. I have a number of my pictures published in magazines..... pix that were shot down by one or another micro and accepted by others. These were handled directly by the editors and art directors working for the publishing company. More to the point, these were pix that were shot down for.. noise and artifacting. Some of these pictures were used in the mags, full page as article covers. So I too often wonder about 'what is too much noise'. I can see if someone wants to blow the thing up the size of a roadside billboard... but they look just fine in the magazine and/or book.
I just had over half of my latest batch shot down by IS for 'artifacting'. These were pix shot over a period of 2 years, interestingly, some in series of shots, where others of the series have already been accepted on IS. I understand they are the boss, it's their site, their business, their rules... no problem... and, honestly,
I'm not complaining here....

I hope to continue to upload to IS, I think I will do well there. (I usually don't do that bad .... in fact I usually do well uploading to IS... just shocked me to see that kind of rejection this time).

Ain't no biggie, just confusing, don't get the rationale sometimes... I just smile, sit back and take another sip of beer. LOL Guess I need to invest in Noise Nija or something... I've been in the business for a year now and have never used a 'denoise' program. Suppose I'll have to learn.

-tom

a.k.a.-tom · « **Reply #16 on:** July 10, 2007, 18:59 »

Quote from: hatman12 on July 01, 2007, 13:58

Yes Tom I agree wholeheartedly.

However sometimes all the planning in the world doesn't allow for things not seen at the scene or not noticed at the time.

On Saturday I had a three hour studio session with a lovely girl, and I've got 37 'possibles' out of about 120 shots. That's great.

Now if only I had noticed that logo on her jeans..........

Amen, brother!! LOL LOL I just got hit for a Nike logo on the side of a sneaker that you have to blow up to 300% before you can tell what the heck it is... LOL... but, rules are rules...
Ain't no biggie, I can fix it in about 20 seconds and resubmit...
The interesting thing is... I'm selling (or have loaded) that pix on 8 other sites... LOL

To Others: I just want to comment on this thread. This is a perfect example of what a great bunch of people we have here on MSG!!! The help and advice is given so freely in effort to help and encourage those of us new to the business. I appreciate these gestures very much, again, this thread a perfect example! Once again I sincerely send my thanks to Leaf for his efforts and to all you more learned photogs here!!

-tom

Cricket · « **Reply #17 on:** July 14, 2007, 15:30 »

Tom wrote:

To Others: I just want to comment on this thread. This is a perfect example of what a great bunch of people we have here on MSG!!! The help and advice is given so freely in effort to help and encourage those of us new to the business. I appreciate these gestures very much, again, this thread a perfect example! Once again I sincerely send my thanks to Leaf for his efforts and to all you more learned photogs here!!

I second that opinion!!! Thanks to everyone for their replies to this thread.

And tom... I really I like your note about having a sip of beer. I am doing that right now as I am writing this post as it definitely helps in making this noise/artifact topic a little more clearer.

Cricket

leaf · « **Reply #18 on:** July 14, 2007, 17:23 »

Quote from: hatman12 on July 01, 2007, 13:58

Yes Tom I agree wholeheartedly.

However sometimes all the planning in the world doesn't allow for things not seen at the scene or not noticed at the time.

On Saturday I had a three hour studio session with a lovely girl, and I've got 37 'possibles' out of about 120 shots. That's great.

Now if only I had noticed that logo on her jeans..........

yeah, things like that are pretty easy to miss. When you zoom in at 200% all of a sudden you can see that the buttons on the shirt have a logo on them too

I think it is pretty amazing at how much detail shows on high res images.

leaf · « **Reply #19 on:** July 14, 2007, 17:25 »

Quote from: a.k.a.-tom on July 10, 2007, 18:59

Amen, brother!! LOL LOL I just got hit for a Nike logo on the side of a sneaker that you have to blow up to 300% before you can tell what the heck it is... LOL... but, rules are rules...

i'm guessing istock found it.

Even though the reviews at istock can be as varied as any other site - if there is something wrong with a photo - they manage to get it pretty often. They are perhaps the most thorough reviewers out there i think.

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