You have a very gradual gradient over a lot of pixels. Basically you are running out of color values to create a smooth enough transition across those pixels. Easiest solution is to either use a grainy airbrush instead of a perfectly smooth air brush, or to add noise. It will be much harder to tell where the bands are because edges will basically be blended by the variation in pixel values. My preferred solution is to hand paint the gradients with a rougher brush, so they naturally have brush strokes and noise.

Very nice study. Love the light and shadow. Maybe perspective could be improved a bit. It looks somewhat flat, which distracted me slightly, and that could be because the photo is taken from really far away with a telephoto lens. However you could cheat that a bit to angle some lines slightly toward a really far vanishing point, which would add better dimension, and make that beautiful lighting really sing without distractions.

Composition is more of a trial an error, so try some different croppings, flip some elements, and see what you like. Also helps if you have a more solid idea of the story you're trying to depict. The more elements you introduce to your story, the more things you'll have to pull from in your painting. Here is a try. I felt most the contrast in the image was on the left side, so I put our subject on the left side so our eye would be more drawn to him. Also the landscape is guiding our eye that way as well. And the sideview of the horseman wasn't really working for me, so I stole a back view from somewhere. The sky looks pretty grey, which tells me you're filming with a yellow filter. So I decided to emphasize that a bit more, shifted the red hues in the background slightly to orange, and desaturated them a bit. Since the yellow filter kills the blue, the blue pants on the rider were bothering me, so I went with grey. I went with a more intimate cropping that contained the landscape features a bit more, but depending on story, you could choose between a more open feel vs a more claustrophobic one. There is no single right answer, though there are choices that support your story, and choices that don't, so be conscious of the choices you're making and for every choice, ask yourself if it's helping or hurting the story, and you'll have to be somewhat critical and inquisitive to find the better choices. Edit: And after I posted, I realized I created a tangent with the hat and the landscape... don't do that.

2021/8/4. Hello everyone. Here's my new long drawing. Thanks for any advice or suggestion. Have a good day.

Depends on what tool you're using... If you're using graphite, newsprint doesn't work very well, you won't be able to see what you're drawing, especially if you have a light touch. If you're using charcoal or conte crayon, newsprint is great. If you're using markers, you might bleed through on newsprint or printer paper, depending on the marker/quality of paper, but if your hand moves quickly, it's less likely to happen, and not too big a deal if it does. If you like to experiment with different mediums, take that into consideration as well. So think of the combination of your tools when making the decision. Also, nothing says you can't have multiple kinds of paper for gestures... Hope this helps.

Excellent work! There are a few things you might be able to improve. Below I have a manipulated image of your reference with a filter. The white/yellow parts are the highlight, the green is the midtone, the blue is the shadow tones (which include core shadow, reflected light and cast shadow). You are missing some midtone on the bridge of the nose, yours seems to go too sharply from highlight to core shadow. This is more pronounced in the ball of the nose, where a fair amount of midtone is missing. On the nasal ala (wing of the nose) you have a highlight, that's not actually there, it's all midtone. It simply looks lighter because of all the surrounding darker areas. This is an easy and common mistake to make. When in doubt, think about the planes and the light. There are no planes on the ala that face the light directly, so there shouldn't be a highlight. And remember, midtone is part of the light family, and darkest light should be lighter than the lightest dark. And one last point I wanted to make, the contrast seems a little high, you went quite dark with the shadows. This may be intentional to create a better picture, but for Bargue studies, since part of the practice is to discipline control of the values, next time you could challenge yourself to match a more subtle overall look. This will probably take more time, as you will need to build values up slower. But it is quite rewarding. Hope this helps, really great work, keep on sketching!

I think you could put the vanishing points a little farther apart. I see the head as tilted away from us a bit, so I'd draw the horizon line at an angle accordingly. Here is what I'm seeing...

Hey Mengu! Great job on this, the drawing is definitely on it's way to being a really strong one. A couple things I might say are to define your shadow shapes more, and clean up the structure of the hands, more specifically her right wrist feels flat. Also I think if you were to make the face plate of her head wrap the forms of the head more, it would do a lot for determining the lighting. Great job though and good luck!

Interesting... To me a mixed lighting condition most of the time can be though like a diffuse light coming from approximately above or from the window, depending on which is stronger, and shadows should fade a bit quicker. On drawings maybe treat one as a major light source, and mentally tune down some of the others can be good. Nice drawing! Although the leg might be a bit too thick? or maybe the shape is like that