You need a black version of your logo: for a rubber stamp, a laser engraver, a vinyl cutter, a one-colour print job, an invoice header that has to print on a cheap office printer, or a white version to sit on a dark photo. You run it through a black-and-white filter and one of two things happens. Either it comes out in soft greys instead of black, or a part of the logo simply disappears — usually the yellow, orange or pastel part.
Both have a clear cause. We tested three ways of converting on 17 October 2026, in Chrome on Windows 11, with two test logos made so the right answer was known in advance: a JPG on white with a black, a yellow, a light-blue and a red part, and a transparent PNG with a navy ring and an orange block.
What a logo needs is one colour, not grayscale
A black-and-white photo is grayscale: hundreds of shades. A black-and-white logo almost always means one colour: every part of the mark in solid black (or solid white), everything else background. Stamps, engravers, cutters and one-colour printing can't reproduce grey at all; they would turn it into dots or drop it.
What we measured
Average value of each part after conversion, from 0 (black) to 255 (white). The background was white (255) in every case.
| Part of the logo | Grayscale filter | Black-and-white threshold | One-colour logo method |
|---|---|---|---|
| Black | 15 | 0 | 0 |
| Red | 109 | 0 | 0 |
| Yellow | 213 — very pale grey | 255 — gone | 0 |
| Light blue | 195 — pale grey | 255 — gone | 0 |
The grayscale filter is what the “black and white” or “mono” filter in most photo apps does. It keeps how bright each colour looks, which is right for photos and wrong for a logo: the yellow part became a grey so pale (213 of 255) that it barely shows on paper.
A threshold — Photoshop's Threshold adjustment, the “Black and White: 50%” recolour presets in Word and PowerPoint, and the pure black-and-white mode of most converters — turns every pixel darker than a cut-off black and every lighter pixel white. That gives real black, but it still decides by brightness, and yellow and pastel colours are nearly as bright as white paper. Our yellow has a lightness of 213 and the light blue 195; any cut-off below those turns them white, and on a white background they vanish. Moving the cut-off up far enough to catch them starts catching the grey anti-aliased edges and the faint JPG noise around everything else.
The transparent-logo version of the trap is worse
On the transparent PNG, the threshold kept the navy ring black but turned the orange block white — 0% of it stayed black. On screen, over the checkerboard, you might not notice. Printed on white paper or engraved, the block is simply not there, because white ink on a transparent background is invisible on anything light.
The method that keeps every part
A logo isn't a photo. The question to ask about each pixel isn't “how bright is it?” but “is this the paper, or is this the logo?”. A pixel belongs to the logo when it is clearly not white — when at least one of its red, green and blue values is well below the maximum. Yellow (250, 210, 0) has a blue value of 0, so it is obviously ink, however bright it looks. Light blue (160, 200, 235) has a red value of 160: ink. A faint grey JPG speck at (245, 245, 245) is paper. Converted that way, all four parts of our test logo came out solid black (0), the background stayed pure white, and on the transparent logo 100% of the orange block was kept.
Step by step
- Start from the best file you have. A PNG or SVG export from whoever designed the logo beats a screenshot or a JPG from a website. An SVG needs turning into a large PNG first: SVG to PNG at 2,000 pixels wide or more keeps the edges smooth.
- Open Black and white image and drop the logo in. Nothing is uploaded.
- Choose Style: Logo — every coloured part black. The result appears straight away and says what share of the picture is now ink.
- Check the pale parts. If a very light tint (a pale cream, a 10% grey) was treated as background, move the slider right. If grey edges or JPG specks around the logo turned black, move it left.
- For a dark background, set Ink to White. The logo becomes solid white; a transparent background stays transparent, so it can be placed straight onto a dark photo or slide.
- Save as PNG. The page writes a 1-bit or 2-bit PNG and opens it again to confirm it contains only pure black (or white) and transparent or white pixels. JPG would add grey along every edge.
Details that trip people up
- White details inside the logo stay white. Lettering knocked out of a black shape, or a white highlight, is “paper” by this rule, so it keeps its shape.
- Two parts in different colours that touch become one black shape. If the design relies on a red next to a blue to separate two areas, a one-colour version needs a thin white gap between them, which only the designer can add.
- The logo sits on a coloured box. If the background itself is a colour rather than white or transparent, it turns black too. Make the background transparent first with make background transparent, then convert.
- Soft edges. Semi-transparent edge pixels are kept if they are at least half opaque. For a vinyl cutter or engraver that traces the outline, a large PNG gives a smoother trace than a small one.
- Photos or gradients inside the logo. A one-colour version can't show them. Choose the dot style instead, which renders shading as a pattern of black dots that engravers and one-colour printing can reproduce.
Quick answers
Why did my logo turn grey instead of black? The app used a grayscale filter, made for photos. Use a one-colour method instead.
Why did the yellow part of my logo disappear? A black-and-white threshold decides by brightness, and yellow is almost as bright as white. A method that asks “is this colour or paper?” keeps it.
How do I make a logo white for a dark background? Convert it to one colour with the ink set to white and save it as a transparent PNG.