First time dryplates development stripes

[PatrickMarq]

That the image is underexposed and the hood is visible is my fault. I was in a rush and find not take the time to check everything.
This is a Zebra dryplates and the holder for the SP-445 are from Nejc.

I don’t have or can create a darkroom so all my development goes in a Stearman SP-445.
So if you zoom in on the building and below you see some stripes, could it be the development ?
Kodak HC-110, 1+31 for 5 min in 20°. First min gentle twist and then every minute 10 sec.
Afterwards the usual stopbad 1 min from Ilford and 5 min fixer.

[PatrickMarq]

I think I might found the problem, it seems that there is some gap where the sliders go in.

[paulbarden]

That the image is underexposed and the hood is visible is my fault. I was in a rush and find not take the time to check everything.
This is a Zebra dryplates and the holder for the SP-445 are from Nejc.

I don’t have or can create a darkroom so all my development goes in a Stearman SP-445.
So if you zoom in on the building and below you see some stripes, could it be the development ?
Kodak HC-110, 1+31 for 5 min in 20°. First min gentle twist and then every minute 10 sec.
Afterwards the usual stopbad 1 min from Ilford and 5 min fixer.

Hand made dry plates are imperfect. I suspect you are just seeing manufacturing artifacts, which is to be expected, to a degree.

[jim_jm]

I found that it's critical to agitate as gently as possible during all stages of dry plate development. The emulsion is very fragile when wet. Haven't used Zebra plates, only J Lane plates but I expect exposure and processing to be very similar. I develop in open trays under a red safelight, rocking the tray gently for 15 sec once every minute.
There are sometimes various artifacts seen after development, but that's just the nature or hand-coated dry plates. That could be the cause of your streaks seen here. if your agitation motion is random enough, that's probably not the cause.
Exposure of dry plates is trickier than film, due to the lack of red sensitivity. The exposure charts on the manufacturer's site are a huge help until you get more experience. I had plenty of underexposed dry plates when I started using them, so it just takes lots of practice to anticipate correct exposures.
This looks a lot better than my first efforts - exposure is not too far off and nicely composed.