For 'format painter', see this discussion.

To change the paragraph spacing to a single line, uncheck 'Use paragraph format...' in Tools/Options/Composition/General/HTML. To set a custom spacing, you will probably have to enter HTML for some parameter such as margin-bottom.

If you install a dictionary(s), TB will spellcheck as you type, spellcheck before sending, and suggest corrections from the context menu.

Many thanks S F Howes for both your replies.

I hope to soon get round to trying these out, and hope to let you know if I've managed this.....

I've used a bit of basic HTML with its angle brackets '< >', but the CSS script was new to me - I've never come across the use of those curly brackets '{ }', nor the measurements 'em' and 'px', or what these mean.

Is this CSS script something that's used for Thunderbird email, or could I use normal HTML instead?

However, I'm a bit scared of downloading things, and will probably get my 'computer guru' to be there whilst I do that - or get him to do it!

Many thanks again!

CSS is just another component of HTML, and you can enter css elements from Insert/HTML... in a TB Write window (or with an HTML add-on).

If you create a message with significant HTML and wish to reuse it, consider message templates (Stationery add-on).

Thanks again SFHowes.

Afraid I'm not very expert with things like HTML / CSS, or when to use which one when and with what.

If what I want to set up means I must use HTML / CSS, I really just need 'dictionaries/glossaries' for these (if that makes sense), where I could look up the right abbreviations to use - and better still, CLEARLY showing where to leave spaces or not, and which type of brackets to use, ( < or } ) etc.

Incidently, I have Thunderbird version/edition: 52.3.0, so I don't know if this would affect how things come out etc.

What I would like to do:

When writing emails I'd like to set my paragraph spaces to be narrower by default.

I'd also like to find a default 'word wrap' setting, so that my messages come out narrower.

There are several online guides to html and css, but if you really want to control the formatting of your messages, it's probably easier to just send word processor or pdf attachments. Most email programs, including TB, allow the user to control the display of email, besides the fact that email is read on a variety of devices and screen sizes.

The width of plain text messages you compose is controlled by the mailnews.wraplength preference. To change the width of html messages I think you have to set the paragraph width as described here.

Well, the furthest I got was being able to set the mailnews.wraplength preference to '0', which at any rate stops the text shooting off the edge of the screen.

I get the impression, from what Ive been told, that it's not practicable to try and fix the body text wordwrap width (I wanted 50 characters) as it can come out awkwardly on recipient's screens, and especially if it's received on a tablet or phone screen?

I continue to - and prefer to - use a widescreen desktop computer, and I realize I'm probably in a minority here!

Sorry - but what is a 'word processor' attachment? Is this distinct from just an attachment of a document that I've saved in my Documents folder?

Catherine Barber UK said

Sorry - but what is a 'word processor' attachment? Is this distinct from just an attachment of a document that I've saved in my Documents folder?

By that I meant something like a Word document, where you can specify formats that will be transmitted to the recipient because such documents have to be viewed in a word processor application, independent of email software.

You can make your composition window narrower to make the text wrap to a comfortable width. The human eye/brain system isn't comfortable with very long lines, but as I have tried to explain elsewhere, fixing your line lengths to an absolute value isn't good for your correspondents. But you can reduce your window width to something comfortable to you and just have the text soft wrap, or flow, to fit. Your correspondents can do the same.

Email is decidedly NOT "wysiwyg". It's not realistic to expect your correspondents to see it on their screens as you see it when you compose. I think it's largely futile to get too precious about layout, formatting, fonts, etc in email. If these aspects matter, then create a document in your word processor, and send it as an attachment in a format mutually agreed between you and your correspondent. PDF is a good fallback as it is designed to be viewable on all commonly use platforms.

Yes, I see what you mean. If a recipient wanted to read my message with a narrower width text body they could simply narrow down their own window-width. If I want a complicated layout for my message then, yes, I would do this on a Word doc and attach this to my email.