Production tips to get rid of artifacts and digital limitations

lolo

Hello!, i want to start a thread for everyone to add their tips and tricks to get rid of the commpression issues, if someones add his own, please use the same format, here are mine:

Banding:

example: i´m shooting a sunset with the gh2

set the proyect settings to 16bit
double the layer
on the upper layer isolate the banding area, can be rotoscoped, or keyed out, in this example is easy to key out the sky as it is only made of one color
on the bottom layer use a blur effect

--pros: it truly gets rids of the banding

--cons: is useful only for soft areas with not much detail, but then again, banding almost always appears only on these areas

Dynamic range:

example: im shooting an actor on a bedroom, and a window is in frame, therefore i´m in backlight against the sun, so either i blow up the window or i underexpose for the actor, unless i increase the light of the bedroom, i have to choose, here is a trick:

Camera must be stationary (over a tripod)
Shoot the scene, exposing for the talent
Without changing the frame, shoot again with no actor, exposing for the window
Mix both shoots on the editor, rotoscoping the window against the actor.

--pros: increases the dynamic range of a camera, gives more information for color grading

--cons: the camera shouldnt move, and rotoscoping is tedious

Vitaliy_Kiselev

@lolo

Please format posts properly as I did for you, click on Format Help.

fatpig

try neat video, it has some very useful capabilitites to reduce blocking and banding :)

BurnetRhoades

General: I'd suggest setting your project to 32bits not 16bits. Work float, not integer. It's not too much to ask of even five year old computers. Learn to love working with normalized, decimal numbers, not that other silly, antique way of arriving at "precision".

Banding: Dither/grain gets rid of banding. It's often aesthetically pleasing as well. It can also be keyed and often is when this task is performed at high end post facilities working with DSLR footage.

Noise Reduction: Apply noise reduction to targeted portions of your image through keying, or re-apply specific results from noise-reduction back to your image through keying. Noise reduction is a lossy process that can destroy detail the same as noise and the simple filters found in most editing software can't tell the difference between the two.

For example, if you're working at high ISO and have lots of noise and blocking in your blacks use a luminance key to target just these areas. Similarly, you might find heavy noise/blocking in highly saturated blue portions of your image. De-noise and/or even median filter a copy of the image and then re-apply this filtered chroma back to your comp with the COLOR transfer mode, through a key that isolates just the offending color channel or hue range.

Color/Luma Purity:

When applying heavier than mild color correction, filters affecting hue, saturation, etc., do this to a duplicate clip and then composite that back over your original clip using the COLOR transfer mode and you'll undo/avoid the luminance pollution introduced by the color filters. Even the highly targeted color-specific operations found in something like Shian's ColorGHear often affect the image's final luminance and/or gamma, visible to the eye and confirmed on scopes. This method preserves the luminance of your "tech pass".

Be aware, you can get some bizarre results once you start operating on luma and chroma separately if you're not careful but once you're comfortable thinking about your grade this way you can create looks that would be very difficult to duplicate with filters and modifications that affect your image as a whole. You can often manipulate and push colors, even from compressed, sub-sampled sources, further than you'd normally have a right to expect this way.

Sharpening: Similarly, apply sharpening only to the luminance portion of your image (use the above method to re-instate the color portion of your grade). You don't necessarily have to labor over some elaborate keying or other method to do this. Just apply the sharpening method of your choice to the bottom clip and use the COLOR transfer method described above to promote your graded, non-sharpened chroma to your now sharpened luminance.