Adjust brightness before a collage

What 0, 100, and 200 do

The sliders are not a collage

There are three controls, labeled Brightness, Contrast, and Saturation. They start at 100. Reset puts them back to 100, and it also clears rotate and flip. The download button says Download PNG. The filename is edited_ plus a timestamp, and the type is PNG.

Rotate turns by 90 degrees each click. A 90 or 270 degree turn swaps the export width and height. Flip Horizontal and Flip Vertical mirror the image. Those transforms are part of this page, and they are baked into the PNG. They are not stored as settings the collage can reopen.

The tool does not crop, does not set a canvas size, and does not cut a grid. If you need 1080×1350, that is the collage, after this export. If you need nine files, that is split photo, after this export.

Hand the PNG to the next tool

1. Move one slider. Leave the others at 100 if you only mean to brighten or darken.
2. Press Download PNG. Confirm the file opened as a picture, not as a half-written download, before you close the tab. Closing the tab drops the original from this page.
3. Open the collage or split photo. Use Upload Photo and choose the edited PNG. The next tool sees pixels. It does not see that brightness was 120.
4. If the collage export looks wrong, fix it here and export again. There is no undo that reaches back from the collage into these sliders.

What this page will not claim

100% is “unchanged” for the CSS filter the canvas uses: brightness(), contrast(), and saturate(). It is not a lab measurement of the file’s histogram. 200% means the filter value is 200, which is twice the 100 baseline for that function. It is not a promise about a camera stop.

The sliders do not stack with a second visit. If you upload the exported PNG and set brightness to 200 again, you filter an already filtered file. Reset does not recover the camera original once you have left the page. Keep the original on disk if you might want it.

There is no account, no watermark, and no upload of the photo to Collage87. The privacy policy is the binding page for analytics. This tool does not send the image to Google Analytics either.

One photo, one pass

Take a 1000×1500 photo. Leave contrast and saturation at 100. Move brightness to 130. Download PNG. The file should still be 1000×1500, named edited_ and a timestamp. Rotate once before that download and the file becomes 1500×1000, because 90 degrees swaps the sides. The sliders do not add pixels.

The three numbers go into one filter string, not three separate passes. Brightness 150 with the other two left at 100 is brightness(150%) contrast(100%) saturate(100%). The range inputs step by 1, so the value beside the slider is a whole percent. The preview applies that same string as a CSS filter. Export draws with the canvas filter. Both read the numbers on the sliders. Reset sets all three back to 100 and clears rotate and flip. It does not reload the file from disk.

Upload that PNG to the collage if you want a frame around it. The collage opens at 1200×1200. A photo dropped in a cell is scaled to cover the cell, so a 1000×1500 photo in a square cell loses the top and bottom of the frame. That crop is the collage placement. The brightness file itself is still 1000×1500. If you only wanted the photo brighter, stop at the PNG.

Split photo is the same handoff. The ZIP is cut from the edited file. A 3×3 with gap 0 on a 1000×1500 image is not nine squares. Each piece keeps the source ratio. If you needed squares, crop before the split, or start from a square file. This page will not crop for you.

Questions