Guide 4 of 5 in Level 2: Make your first post

Edit slides, captions and alt text

To edit a post in Blackbox (blackbox.plus), open it from Plan and click Edit slide on the preview. Click the words on a slide and type; a slide fits a 70-character headline and 35 words in all, and it saves when you click away. To have them rewritten, click a chip such as Shorter or Stronger hook, or say what to aim for and click Rewrite; nothing changes until you click Keep. In the strip of slides you can reorder, add, duplicate or delete, keeping a carousel between 2 and 10 slides, and Undo, Redo or History brings back any change. Under Alt text, describe what each slide shows, up to 1,000 characters. Then open step 1, Caption, write it, and use Refine to change it the same way. Suggest hashtags offers some to tick, and the first press is free. Posting to Instagram and TikTok together splits the caption into two tabs. A scheduled post is locked, so unschedule it first.

You'll need
Time
About 5 minutes 11 steps Updated
You'll end with
Slides, caption and alt text the way you want them, with nothing left on Check
Do it in Blackbox Open Plan, after you sign in
Example
Changing a slide, its alt text and the caption

How to edit slides, captions and alt text in Blackbox

  1. Step 1:Open the slide editor

    Open the post from Plan and click Edit slide on the preview.

    You'll see: The editor, open on that slide.

    Open this in Blackbox

  2. Step 2:Change the words

    Click the words on the slide and type.

    You'll see: A counter for the 70-character headline and 35 words in all.

  3. Step 3:Or have them rewritten

    Under Words, click a chip such as Shorter or Stronger hook, or type a note under Anything to aim for? and click Rewrite.

    You'll see: Rewrite beside your note, under the five chips.

  4. Step 4:Keep or discard the new words

    Click Keep to put the new words on the slide, or Discard to leave it as it is.

    You'll see: The new words beside Now, the slide’s words today, with Keep and Discard under them.

  5. Step 5:Arrange the slides

    Drag slides in the strip to reorder them, or use the ‹ Move › arrows, + Add, Duplicate and Delete.

    You'll see: The slides in their new order, saved on their own.

  6. Step 6:Add alt text

    Under Alt text, describe what the slide shows, as you would to someone who can’t see it. Click Done when you’re finished.

    You'll see: The post again, with your slides updated.

  7. Step 7:Write the caption

    Open step 1, Caption, and write the caption.

    You'll see: Counters under the caption for 2,200 characters and 5 hashtags.

  8. Step 8:Refine the caption

    Click Refine and pick a change, such as Shorter. Click Keep to use the new caption, or Discard.

    You'll see: The new caption under yours, with Keep and Discard.

  9. Step 9:Add hashtags

    Click Suggest hashtags under the caption, then tick the ones you want.

    You'll see: Hashtags to tick, each one you tick added to the caption.

  10. Step 10:Write the TikTok version

    Posting to Instagram and TikTok together? Open the TikTok tab under Caption and click Write the TikTok version.

    You'll see: TikTok’s own Title and shorter Caption, which you can edit.

  11. Step 11:Check what is left

    Open step 2, Check.

    You'll see: What is left: the caption, slides still drawing, or a slide without alt text.

Good to know

  • The five chips are Shorter, Stronger hook, Add a call to action, In the brand’s voice and Fix grammar. The caption’s Refine menu has the same five, and each uses one of today’s rewrites.
  • The first Suggest hashtags is free. Suggest again asks for a new set and uses one of today’s rewrites, as Write the TikTok version does.
  • Regenerate this slide, at the top of the editor, writes new words for that one slide in the same layout and style, and a new picture when that slide has one; it uses one of today’s rewrites, or a picture, and isn’t charged if it fails. Redo all slides, on the post, rewrites every slide and the caption; slides marked Keep as is stay.
  • One caption by default. The Instagram and TikTok tabs appear once both kinds of account are picked on the Post step. Leave TikTok’s empty to use the Instagram caption.
  • Track visits from this post adds tracking to your ask’s link, so visits from the post show up in your site’s analytics.
  • There is no Save button: each change saves on its own, and History keeps the version before every edit, with the name of whoever made it.
  • Under Layout, you can move the words to the Top, Middle or Bottom, or make the headline Smaller or Larger.
  • Alt text is up to 1,000 characters, and Blackbox sends it to Instagram with each picture. Missing alt text is a reminder on Check, not a blocker.
  • With your own uploaded pictures, the button says Edit slide (Arrange slides on a video as uploaded), and the editor reorders and deletes them.
  • A carousel holds 2 to 10 slides.

Official docs

If something doesn't work

My caption gets cut off on Instagram

Instagram shows only the start of a caption until someone taps more. Put the point in the first line, say one thing, and end on what to do next.

Check says a slide has no alt text

It is a reminder, not a blocker. Alt text is read aloud to people who can’t see the image — open Edit slide and describe it under Alt text. It takes a minute.

I want a different caption on TikTok

Pick both your Instagram and TikTok accounts on the Post step, then open the TikTok tab under Caption and click Write the TikTok version, or type your own. TikTok gets its own title, up to 90 characters, and its own caption.

There are no hashtags under the caption

Hashtags are suggested only when you ask. Click Suggest hashtags under the caption; the first set is free. Write the caption first if the button is greyed out.

It says Not saved

The words did not fit the slide: a headline is required, it fits 70 characters, and a slide fits 35 words. The message says how much to cut.

I changed something by mistake

Click Undo (or press ⌘Z), and Redo (⌘⇧Z) if you went back too far. For anything older, open History, which shows who made each change, and click Restore next to the version you want.

Stuck at any step? Send us a message and we'll do it with you on a call. All of Level 2: Make your first post