Hi Andre, thanks for responding.

I'm not going to try your suggestions.

The printer was initially setup from brand-new, so is already at factory-defaults, never having been changed from those defaults.

CUPS requires printer-specific setup. CUPS itself is printer-agnostic & requires instructing on the specifics required for a specific printer; that is the purpose of the PPD text-files. The only way that your DCP-L2550DW could have been auto-setup without an external driver is if it used the CUPS-supplied ppd file. I've already confirmed that the CUPS-supplied driver for my model is identical to the Brother-supplied driver that does not perform. I'm not going through that all over again. But again, thanks for trying.

Extra: I see that your printer has an option for IPP Network Printer. That also uses the CUPS database, so may well have the same problem as the USB connection that I'm using. Ah, spit.

I think that Android 5 was the last that let you do what you want to do, which essentially is to mount the Android 'disc' on a foreign machine. The only means of USB connection with Android 6 & higher is via MTP ('Media Transfer Protocol') which, essentially, is connection via modem. It thus prevents any mounting of the Android electronics on anything other than Android localhost.

Because of the above lsusb becomes ineffective.

Brother-DCP-L3510CDW-ppd.zip

$ 7z l Brother-DCP-L3510CDW-ppd.zip

7-Zip [64] 16.02 : Copyright (c) 1999-2016 Igor Pavlov : 2016-05-21
p7zip Version 16.02 (locale=en_GB.UTF-8,Utf16=on,HugeFiles=on,64 bits,4 CPUs AMD A8-7410 APU with AMD Radeon R5 Graphics     (730F01),ASM,AES-NI)

Scanning the drive for archives:
1 file, 244572 bytes (239 KiB)

Listing archive: Brother-DCP-L3510CDW-ppd.zip

   Date      Time    Attr         Size   Compressed  Name
------------------- ----- ------------ ------------  ------------------------
2017-08-23 14:45:14 .....        30733         6653  BRPPL3510CDW.ar.ppd
2017-08-23 14:45:08 .....        31172         6734  BRPPL3510CDW.bg.ppd
2017-08-23 14:45:08 .....        30823         6673  BRPPL3510CDW.cs.ppd
2017-08-23 14:45:10 .....        30748         6661  BRPPL3510CDW.da.ppd
2017-08-23 14:45:10 .....        30768         6681  BRPPL3510CDW.de.ppd
2017-08-23 14:45:08 .....        30989         6649  BRPPL3510CDW.en-1.ppd
2017-08-23 14:45:10 .....        30609         6617  BRPPL3510CDW.en-2.ppd
2017-08-23 14:45:14 .....        30617         6617  BRPPL3510CDW.en-3.ppd
2017-08-23 14:45:12 .....        31115         6711  BRPPL3510CDW.es.ppd
2017-08-23 14:45:10 .....        30897         6685  BRPPL3510CDW.fi.ppd
2017-08-23 14:45:10 .....        30958         6704  BRPPL3510CDW.fr-1.ppd
2017-08-23 14:45:10 .....        30970         6707  BRPPL3510CDW.fr-2.ppd
2017-08-23 14:45:10 .....        30878         6683  BRPPL3510CDW.hr.ppd
2017-08-23 14:45:10 .....        31071         6740  BRPPL3510CDW.hu.ppd
2017-08-23 14:45:10 .....        30804         6666  BRPPL3510CDW.id.ppd
2017-08-23 14:45:10 .....        31011         6693  BRPPL3510CDW.it.ppd
2017-08-23 14:45:10 .....        30431         6617  BRPPL3510CDW.ko.ppd
2017-08-23 14:45:12 .....        31125         6723  BRPPL3510CDW.ls.ppd
2017-08-23 14:45:10 .....        30761         6673  BRPPL3510CDW.nl.ppd
2017-08-23 14:45:12 .....        30693         6651  BRPPL3510CDW.no.ppd
2017-08-23 14:45:12 .....        31092         6767  BRPPL3510CDW.pl.ppd
2017-08-23 14:45:12 .....        31118         6735  BRPPL3510CDW.pt-1.ppd
2017-08-23 14:45:12 .....        31024         6709  BRPPL3510CDW.pt-2.ppd
2017-08-23 14:45:12 .....        30962         6726  BRPPL3510CDW.ro.ppd
2017-08-23 14:45:12 .....        31190         6760  BRPPL3510CDW.ru.ppd
2017-08-23 14:45:12 .....        31043         6744  BRPPL3510CDW.sk.ppd
2017-08-23 14:45:16 .....        31125         6723  BRPPL3510CDW.sl.ppd
2017-08-23 14:45:12 .....        30971         6698  BRPPL3510CDW.sr.ppd
2017-08-23 14:45:12 .....        30833         6684  BRPPL3510CDW.sv.ppd
2017-08-23 14:45:12 .....        30679         6701  BRPPL3510CDW.th.ppd
2017-08-23 14:45:12 .....        30849         6726  BRPPL3510CDW.tr.ppd
2017-08-23 14:45:14 .....        31246         6791  BRPPL3510CDW.uk.ppd
2017-08-23 14:45:14 .....        30828         6646  BRPPL3510CDW.vi.ppd
2017-08-23 14:45:08 .....        30213         6521  BRPPL3510CDW.zh-cn.ppd
2017-08-23 14:45:08 .....        30492         6558  BRPPL3510CDW.zh-tw.ppd
2019-07-03 13:53:57 .....        26326         4497  DCPL3510CDW.original.ppd
------------------- ----- ------------ ------------  ------------------------
2019-07-03 13:53:57            1107164       238524  36 files

It's fully-updated Chromium. If that doesn't work then sod it.

It doesn't look like any ICC profile will do any good here. I may have run out of options to fix this model so that it will print colours OK. Bugger.

This link to cityinkexpress.co.uk will help explain what ICC Profiles are normally used by print shops to achieve.

In a nutshell, the biggest problem for a printshop is when a customer's home-produced printout on *their* printer looks lovely in their business/home, and all wrong from the Print Shop. So, City Ink Express provide a Colour Chart for the customer to printout using their printer. The customer then posts (or delivers) the printout back to the shop. City Ink Express have a piece of software ("advanced color calibration software") that scans the printout & produces an ICC Profile (software file) which is emailed back to the customer. The intention of the profile is to shift colour differences between the customer's printer & the commercial printer, so that (as much as possible) the commercial printout looks as close to the home printout as possible. The main issue for me is that no details of how that profile is used are revealed.

You can probably see why the above excited me re: my problem, and specifically because I had seen references to "Profile" whilst printing. Nope, wrong kind of Profile.

Brother has a Printing Profile, but you can tell from the link that it is nothing to do with shifting colour balances.

"ICC Profiles" feature exactly nowhere in brother.com. What *does* feature is "Windows ICM Profiles". That link states that these are provided on the driver CD at "x:\driver\ps\icm". Not on the CD for the DPL3510CDW they arn't. Yet another blind alley.

The final blind alley was me trawling through all the MSI files on the CD yet again, this time looking for "Profiles". Or even "ICC" or "ICM". Just in case. Nope. None. Nada.

I've also tried to find an address at which to report the Dead Fish that is the CUPS driver for the DPL3510CDW. I found a Reporting Issues information page. The one missing item was either an email address, a website page, a telephone number or even the location of a stone in a park to place the secret paper underneath. It seems like they don't want to know.

And with that final big NO I must leave this report.

Where's the NOT SOLVED button?

(re: ICC_Profile_Creator)

Well, that looks awesome (hurrah)
Ah, it is integrated into rawtherapee (boo)
But rawtherapee is open-source (hurrah)
The AppImage is 108 MB (boo)

Bugger. And I strongly suspect that the profile created is directly related to the screen (meaning, do colours from *any* program show accurately on the screen). I've already got & use a profile for that (and it isn't even a high-performance screen).

Still, no matter. That was a superb find. I now need to find whether the Profile-Maker can be installed independently of the entire program†, and whether that can be used for a printer. I'm also shortly going to trawl through the Brother win-drivers again looking for a profile. I also need to find the way to communicate to CURL (which I think is also openprinting.com) that their current Brother DCP-L3510CDW PPD is pants, and to offer the derived-from-windows collection (69 separate files‡).

† Feb 6 update: I did check & the GitHub site shows a single file to create the utility. However, it is thoroughly integrated into the whole program, with dozens of calls to other sections
‡ Feb 6 update: 35 PPD files after removing dupes

I certainly agree with the (non-existent) Profile file as being a likely source for the problem. That was my early suss when first trying to fix this beast. The fact that there is less problems with the CMYK driver than the RGB driver points in the same direction (as far as I understand these things). However, how do I get such a file? I managed to get one for my monitor from an old Windows driver, but that was a Monocoque, so there was only one place to look.

@delgado:
The Brother is 600dpi and generally colours are good (recall that it is CMYK, same as printing inks). They are simply wrong!

The OP detailed my problem; in a nutshell:

• Having paid out shed-loads of money to Amazon for a LED-powered printer/copier/scanner/wlan CMYK-toner network printer and,

• having downloaded an up-to-date Linux driver from the Brother website,

• discovered that it completely screwed up the colour balance in both text & photographs and,

• Brother just responded with handy-wavy gestures & did nuthin'

To rub salt into the wound, I saved a file that was giving print difficulties as a PDF, took it to a friend with a business, and used his HP DeskJet to print it out (flawless). Bah!

Very recently I discovered that the key to ALL printing (regardless of your OS) is a PPD file. These were originated by Apple (as I understand it), and Adobe is in there somewhere. They are plain-text configuration files for PostScript and, mostly, are to specify ways in which printer-specific services are to be configured, and how things differ from the defaults. Here is the CUPS Help file (link only works if you have CUPS installed):

The Printer Queue shows icons for each installed printer. CUPS uses a PPD file at install-time, in the process creating that icon(s):

Here is the head of each file so that you can get a handle on what they are like:

$ sudo head /etc/cups/ppd/BRPPL3510CDW-CMYK.ppd -n 40
*PPD-Adobe: "4.3"
*%================================================
*%	Copyright(C) 2017 Brother Industries, Ltd.
*%	"Brother DCP-L3510CDW BR-Script3"
*%================================================

*%==== General Information Keywords ========================
*FormatVersion: "4.3"
*FileVersion: "1.0"
*LanguageEncoding: ISOLatin1
*LanguageVersion: English
*Manufacturer: "Brother"
*PCFileName: "BRPPL3510CDW.PPD"
*Product: "(Brother DCP-L3510CDW)"
*PSVersion: "(3010.106) 3"
*ShortNickName: "Brother DCP-L3510CDW BR-Script3"
*ModelName: "Brother DCP-L3510CDW BR-Script3"
*NickName: "Brother DCP-L3510CDW BR-Script3"

*%==== Basic Device Capabilities =============
*LanguageLevel: "3"
*TTRasterizer: Type42
*ColorDevice: True
*DefaultColorSpace: CMYK
*FileSystem: True
*?FileSystem:"
save 
	/devname (%disk0%) def 
	/ret false def 
	0 1 7{ 
		devname exch 48 add 5 exch put 
		devname devstatus { 
			0 ne {/ret true def}if 
			pop pop pop pop pop pop pop 
		}if 
	}for 
	ret {(True)}{(False)} ifelse = flush 
restore 
" 
*End

$ sudo head /etc/cups/ppd/DCP3510W-RGB.ppd -n 40
*PPD-Adobe: "4.3"

*%================================================
*%	Copyright(C) 2018 Brother Industries, Ltd.
*%	"Brother DCP-L3510CDW for CUPS"
*%================================================ 

*%==== General Information Keywords ========================
*FormatVersion: "4.3"
*FileVersion: "4.0.9"
*LanguageVersion: English
*LanguageEncoding: ISOLatin1
*PCFileName: "DCP3510W.PPD"
*Manufacturer: "Brother"
*Product: "(DCP-L3510CDW)"
*1284DeviceID: "MFG:Brother;MDL:DCP-L3510CDW"
*cupsVersion: 1.4
*cupsManualCopies: false
*cupsFilter: "application/vnd.cups-postscript 0 brother_lpdwrapper_dcpl3510cdw"
*%cupsFilter: "application/vnd.cups-pdf 0 brother_lpdwrapper_dcpl3510cdw"
*cupsModelNumber: 5
*ModelName: "Brother DCP-L3510CDW"
*ShortNickName: "DCP-L3510CDW"
*NickName: "Brother DCP-L3510CDW CUPS"
*PSVersion: "(3010.106) 3"

*%==== Basic Device Capabilities =============
*LanguageLevel: "3"
*ColorDevice: True
*DefaultColorSpace: RGB
*FileSystem: False
*Throughput: "17"
*VariablePaperSize: False
*TTRasterizer: Type42
*FreeVM: "2700000"
*DefaultResolution: 600dpi
*%DefaultOutputOrder: Reverse

*%=== UI Constraints ==================================
*UIConstraints: "*BRInputSlot AutoSelect *BRMediaType Label"

So, first I had to find a PPD file that would actually work. That was simple, if fiddly, once I found it, and is detailed in the OP. I then hoped that simply replacing the file located in /etc/cups/ppd with the new file renamed-to-the-old would be sufficient but, naturally, that was a foolish hope. There is an actual install process to go through, and that will be detailed in the next post.

Don't do this with Chimaera:

W: Skipping acquire of configured file 'non-free-firmware/binary-amd64/Packages'
 as repository 'http://deb.devuan.org/merged chimaera InRelease'
 doesn't have the component 'non-free-firmware'
 (component misspelt in sources.list?)

Edit: reset since code is too stupid to wrap lines to the page

Sounds like port-80 is blocked for external traffic. But of course, that would mean that nf_tables (or something) is running.

Sorry, but cannot help. I was competent with the old firewall, but know nothing about the new one(s).