Always work in 16bit ?

(Mica) #21

Do we really need statements like this? Not only are they mean-spirited, but this kind of hyperbole only serves to undercut the rest of your statement(s).

(Aurélien Pierre) #22

Yes we do. The issue of “experts” using their authority to propagate fake knowledge should be adressed with the utmost firmness.

(Mica) #23

You may still address it with firmness while not saying those kinds of things. In fact, omitting those types of communications make people more likely to believe what you’re saying, improve their own practices, and engage with you further.

On the other hand, being condescending and hyperbolic only makes people avoid you.

(Aurélien Pierre) #24

Yes, I’m well aware that the 2010’s are all about the form, and little about the content. Being nice is more important than being accurate or competent. The thing is, when people ask for disdain, disdain I give them. It’s one thing to be wrong, that happens to everyone. It’s another to be wrong your whole carreer and not discover it. But, again, that can happen. What is unforgivable is to teach your wrongness for money where you could maybe have done some research before and get some clue that your beliefs were not backed up by evidence. That, is asking for my wrath. Comm’on, Internet… You want to be a teacher ? Show some due-process. You are only one click away from Google Scholar.

(Mica) #25

You speak about form and content as if they’re mutually exclusive. They are not.

Nobody asked for disdain.

Still no, nobody is asking for wrath. Or disdain.

I thought the same thing when I read the first sentence of your last post.

Can you please stop those kinds of statements? They’re unnecessary.

(Aurélien Pierre) #26

I think I will stop posting fair and square instead. I don’t live in a state of mind where everyone is nice and trying to improve, and everyone deserves respect for just beeing alive. This world is becoming “Idiocracy” for real, Internet is merely a scope of that, and having to be polite with idiots is making it ok to stay an idiot. I have nothing to win here except grey hair and ulcers, and repeating the same things over and over.

(Pat David) #27

You can be accurate/competent and nice or at least polite. In fact, I’d say it’s a failing if one is unable to muster some tact and politeness when communicating.

(Mica) #28

If that is what you want to do, best of luck to you.

I’m sorry you live in such a sad state. I hope it will improve for you.

(Glenn Butcher) #29

The dynamics of bit precision is one of those many things in imaging that is rooted in a simple concept with complicated implications. The challenge here is to craft the prose that successfully communicates the important concepts to folk who are not computer scientists, folk who want to just create compelling images.

@aurelienpierre, I also have little tolerance for the propagation of misconception. However, I’ve also found there is little to be gained by injecting vitriol into the discourse. Indeed that then becomes the focus, to the distraction from the essential ideas. I find your perspective in the recent topics to be substantial, an imager who has taught himself C++ to improve the state of things. That is no mean feat. And, it has allowed you to see things for what they are, rather than just blindly accepting the status quo. But all that is obscured by the disparagement.

You have authored a darktable module that made it into a release. Don’t think people here aren’t listening…

(Stampede) #30

For the record, I think your comment about the guy digging a hole to shoot himself in is funny. No complaints here.

I think it also demonstrates a difference in mindset between theoreticians and users.

Ultimately, my goal of learning to use photo manipulation software better is to make more powerful images. That is the point of these software programs…to help people make more emotionally powerful images.

Often, when I edit, I’ll try tweaking one parameter in the effect I’m doing, or maybe tweak a little bit the color here or there, and I’ll want to compare my last version vs. the one with the tweak.

If I have to sit and wait 10 seconds on modern hardware/16 GB RAM + decent video card, for the screen to redraw because I’m using ultra technical 1 millien bit floating point, that is an impediment in my creative process. Because it gets in the way of me SEEING the image and comparing one version vs. another.

So when I say, “Does it REALLY matter if it’s 8- or 16- or 32- or 1 billion bits?” I’m looking at the final image I can make with the software. That’s the criteria. Because if I sit twiddling my thumbs while the computer computes every little nuance on its 16 cores every time I touch a tone curve or whatever, that interrupts the creative process.

All I want to do is make the best pictures I can, in the amount of time that I can afford to spend on each picture. If I can process in 8-bits and have instantaneous on-screen updating and the final image doesn’t suffer (much) from this shortcut, then that’s the way to go…in my world.

In your world you seek maximum precision and purity of theory.

The real world gets messy.

It’s a fundamental difference between the technician mindset and the user mindset. I’m not trying to talk shit on technicians. There are a bunch of optics geeks sitting around at Canon right now arguing over some crap about how to design the next lens. I have no idea about their formulas for light diffraction this or that, and I don’t care. But they will do what they do and in a couple years they will release a new lens that enables people like me to make better pictures, and I’m grateful for that and for their work.

Same thing with these softwares. At what point is it OK to start cutting corners? The “technician” doesn’t want to admit that it’s OK to sometimes throw away bit-depth information, even if the user can’t tell a difference using his eye. One person evaluates in the abstract ideal, and ones evaluates in the concrete. Somewhere we need to meet in the middle.

It’s a big world, and there’s room for all of us. The people you say should dig a hole and shoot themselves, have been getting paid to make powerful images for years, and they are successful at it, whether you like it or not. These are the sort of people that our FOSS image software is purportedly written for.

Here’s the portfolio site of the instructor who said 8 bits does the job most of the time. When I look at his site, I’m not seeing 8 bit photos. I am seeing lighting, color harmony and emotions. I see light, colors and emotions like when I look at your website, also. I can’t tell what pix were processed in 16 bits or not. Can you?

I think it’s interesting that I posted a question higher in this thread about if I could use lower bit depth in gimp to make processing faster. I got responses that were several hundred words, which I read a few times to try and make sense of. And I still don’t know the answer to my question.

(Stampede) #31

I love you for this line. The folks who just want to create compelling images NEED the computer scientists to write their software. But there is too often a communication breakdown between the two camps because of competing values and priorities. Personally, I hope to bridge that gap one day if I can acquire the skills and understanding of the software.

(Alan Gibson) #32

I agree.

I like the photos. However, they are fairly small 8-bit lossy-compressed JPEGs. (“Lossy” means the colours have been changed so they compress more effectively.)

JPEG is a useful format for showing photos on the web. But once a photo has been through 8-bit lossy JPEG compression, we cannot guess what formats were used for intermediate results. For example, the compression method will reduce banding, because the process is especially lossy for areas of flat colour.

(Morgan Hardwood) #33

Yes. I’m also seeing JPEG compression artifacts and posterization.

These are visible directly in the image on the website, I just boosted it a little (GIMP Colors > Auto > Equalize) to make it clear.

What does it mean to work “in 16-bit”? There is a whole workflow to consider, from the moment you click the shutter to the final picture on your website. Most of it is not in 16-bit. For example your raw files are likely 12-bit or 14-bit, with probably the lowest bit being insignificant. Then you process your raw files in a raw editor which probably uses 32-bit precision. Then you send an intermediate file to a raster editor like Photoshop or GIMP. Finally you save for the web. Try not to lose data until that final step.

Your instructor uses Lightroom, and Lightroom does not perform calculations in 8-bit. By the time an image comes out of Lightroom it has already been greatly cooked, so from this point you can get away with using an 8-bit intermediate file if you don’t perform heavy tonal manipulations. Of course one can be stupid and use JPEG as an intermediate format, but why would one do that? When you cook, do you always use the absolute smallest pot you can find, hoping that your soup will just touch the brim and not spill over? Use a bigger pot, there’s more headroom and less cleaning up.


The middle for me would means at least 10bit :slight_smile: , 8 bit are really too low quality.

Gimp on my end is too slow for a 16 bit workflow :frowning:

(Glenn Butcher) #35

In that specific realm, it’s either 8 or 16. In the way computers are currently organized, the chunks of data are organized in multiples of 8 bits. That’s why your 14-bit raw data arrives from the file in 16-bit containers.

Performance, capacity, and all that computer crap is secondary to the essential difference between 8- and 16-bit containers relevant to image data: between black and white, 8-bit gives you 256 increments of gradation; 16-bit gives you 65536 increments.

Me, in all the imaging tools I’ve used, where I’ve had a chance to compare 8 vs 16 bit operations, the only place where that aspect has been discernable was in file load/save. But, whatever the performance difference, the decision in which to use for imaging needs to be rooted in the need for the precision of tone gradation. And in that regard, I’ve seen significant difference between the two in PP.

(Pat David) #36

@Stampede I think it can mostly be summed up as:

  1. Work in as high a bit depth as you can to maintain speed and creative flow.
  2. If you must work in a lower bit-depth, try to do so after you’ve needed to do any violent tonal shifts
    a. Maybe move all of your color and tonal pulling earlier in your workflow, and move sharpening, local edits later? Just thinking out loud here.

Or even better, as @ggbutcher states: