If offered a percentage of profit for an ebook (e.g. after Amazon's cut), what is reasonable charge for proofreading a somewhat specialized non-fiction manuscript, written by someone whose first language is not English (to be fair neither is mine)? I realize the answer will be 'it depends', but just wondering if asking for 10%-15% is too much?
If someone asked me to proofread in return for a percentage, I'd turn them down, because I'd want to be paid as soon as the work is done, and I wouldn't want how much I get paid to be dependent on sales of copies.
However, if you want to take them up on it, I guess you should first work out the flat fee you'd be willing to work for, then work backwards from there.
Where n is a reasonable estimate for number of copies the book is likely to seel, p is the net profit on each copy of the book, and s is the minimum sum you want to be paid, then the percentage you should ask for is s / p * n * 100.
The tricky bit is n, as you can't know for sure, but you could look at sales figures for similar titles in that subject area and correlate it with sales of the author's previous titles, maybe?
I mostly wrote plays, and never, ever, have I given the proofreader a cut of the profits.
They got .50 cents a page (a play is about 90-120 pages) and that back in the 80's was industry standard. I have heard novelists from some of my wrtiter's agents say they pay about $1 per page today (well, 5 years ago).
Plays are a lot more difficult to get published, let alone produced. You have to workshop it first, which is doing first readings where the play is read in a monotone, make changes, then at subsequent readings, you need to find real actors to study the character and read the parts. Then you can see if the dialogue works. If your plot holds.
Usually, for me to get a group to do readings like that, I give the play to a community or regional playhouse, and let them put it on without royalties. This way, I get a director, and it goes from being just a set of readings to a dress rehearsal to an actual production. And that is when you stand in the back hoping the audience liked your play.
After its first production, then you can get it published in one of the catalogs. I was a member of the Dramatist Guild for years, and by membership found it easier to get first and second readings.
I would think that a proofreader does the same job as first reader, actor for each of your characters, and critiques more than just your grammar and spelling. They get into the roll of each character, and will identify any flaws and inconsistencies with your characters as it pertains to the storyline and plot.
They also will go over the plot. I use the hero method of plotting for plays, as I only have 90 minutes to get my story across. But a novel can have so many subplots, a good proof reader will let you know what is working and what isn't.
And sometimes, especially if you have an agent, they will insist on a second proof reading after you made the changes to your story.
One thing I did in the theater when I had a play that was good, and this is done in independent movies with low budgets. You give your director, actors, even the sound and camera people equity into the project.
This gives them incentive to do the best job possible, because if they don't, they get smaller checks.
I can see possibly paying a proofreader a piece of the action, but not at 15 percent. An agent will take at least that much, then your publisher (if you don't self publish) takes a huge cut. The deduct the cost of printing the book, and the distributors and retail sellers take cuts as well. Depending on your contract, your publisher and agent get their cut, and it can either be a percentage based on the retail price, or the net proceeds.
These are things you need to know before you you decide whether to just pay the $380 to the proofreader, or cut them in for a small percentage.
And if you do not type your manuscript yourself, services charge between .50 cents to $1.50 a page. But you should only use them when you are ready to send copies to publishers. They don't require a percentage.
Most authors I know whose books sell for $19.99 usually wind up with getting between $1.50 to $3.00 per sale.
This is why many self-publish. Even if you get a contract with a large publishing house, you will still have to hit the road to promote your book. Why not save a ton of money and publish the book under a publishing house you own? Then you can expand and publish the works of other writers and take a percentage from their sales.
Your proofreader, like those who do workshop my play, will make or break your story before you even get your book published. It will mean the difference between getting $1.50 per book or $3.00.
BTW: Even if you hire a proofreader, which is recommended, a publisher will hire their own proofreader. This is how important you proofreader is, because up until then, no one has seen your book. First impressions are everything.