Question about post processing with PS

[jarlaxle2k5]

Hello everybody,

i was trying to process some old data just to check if my skills in post processing are improving and

i have been through so many tutorials and youtube videos that now i got at the point that my mind is literally blowing up for the amount of information and confusion that i have

I saw tutorial starting the process with levels and after curves, other tutorials start with curves and then after set levels and still another tutorial saying that better start playing with brightness, contrast and saturation and star masks.

Now the question is, is there any specific/standard procedure that i can follow in mostly of the cases (for example when i process the Rosette Nebula)?

Thanks for reading

[nmoushon]

There really isn't a standard proceedure so to say. There are more or less standard....guidelines, I guess you could call them, or techniques. Levels and Curves are the very basic of the techniques that are used to bring out the object in the data. Some techniques are used in every post processing and some aren't. Levels and Curves are some that are used every time. I use these to do a 10min post process to see what kind of quality of data I have. To see if my flats/darks/bias are all working good. To see how the noise level is doing so I can judge how many more subs I should do. Also to give myself a nice peek as to what I've captured too. There are many many techniques, programs, plug-ins that are used. Some will always be used and some will be used only on certain objects(types). It really comes down to practice and to see how each technique is used and what it does. Then you apply those techniques as neccessary. I'm still learning this too but its really just practice practice practice. Unless you really want to learn the finer details you could buy some of the more professional tutorials on CD/DVD that are out there. I've never used them so can't say how good they are or not.

[Leveye]

Start with slightly cropping the edges very first thing. Then levels and then curves.

[red dwalf]

I slightly crop the image first to clean up the levels abit, sometimes you get.a.thin line on the start of the levels and cropping the image slightly gets.rid of this.

Then I have.a look at the levels, if they are way over to the right then I use levels first and then the curves, but if the levels are to the left I use curves first and then levels.

It can be very confusing I admit, does my head in.

I also found that when I use deepsky stacker the autosave image comes out better in the finished photoshop image than the saved image it asks you to save.

Especially if i use my canon 1100d, and i never compress the image as i save it.

Very strange but give it a go.

[ollypenrice]

Anyone telling you to stretch in Curves before checking Levels should be banned from the internet! Ignore them.

The advice to crop first is essentailly good but how do you know what to crop until you have checked the edge artefacts by stretching? You can make a copy layer, stretch the top layer till the edge artefacts are visible, apply the appropriate crop and then delete the top layer. Save the result as a linear crop of the original and work only with that. Why do this? Simple; when you want to make a separate new stretch for a different part of the image you will have a perfect fit with what you have already done. If you crop and process then want to start again you will have a hell of a job to duplicate the same crop.

The alternative to cropping is to work within a rectangular selection but I recommend the method above.

It is vital to set the black and white points before stretching. Be very conservative in cutting back the black point because when it's gone it's gone. The final cut back is literally the last thing I do in processing.

You can stretch by moving the grey point to the left in levels, giving a pure log stretch, or you can be clever in Curves by creating dedicated curves for different purposes. The latter, obviously, is more advanced but more tricky. I'd play around with both.

Olly

[red dwalf]

Anyone telling you to stretch in Curves before checking Levels should be banned from the internet! Ignore them.

Alittle bit rude olly !

[melsky]

As someone who has been using Photoshop for 21 years now I always find it strange that levels are preferred to curves for tonal adjustments,

you have exactly the same histogram to guide you behind the curve but instead of just three points of adjustment (black, midtone and white)

you can have multiple points anywhere you like and if you use the drag control (see blue arrow) you can click anywhere on your image and push

up to lighten or drag down to darken whatever tone you like. I would always recommend using these as adjustment layers so you can selectively

mask or tweak them if necessary or just throttle back the effect by reducing the opacity .

Mel

[akjudge]

Olly may be rude, but he is right....

For most beginners, they need to realize that Levels, cropping, noise reduction,Spot Healing Brush,brightness, saturation, grey point adjustments, etc. are stretching the data that is there WITHOUT changing the data.  As soon as you begin using Curves, contrast, hue, etc. you are changing the captured data.  So you should do the LINEAR adjustments (listed above) before actually changing the data with NON-LINEAR adjustments (Curves, hues, etc.).

Jim

[red dwalf]

On a few of my.earlier images i found the levels graph way to the left with very little room for adjustment, is that due to not enough exposure time ?

Sorry for hijacking the thread.

[jarlaxle2k5]

Lads these info are pure enlightment.

I wish i would have asked this before

Thank you so much to everybody, you all have made my day