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Black & White

Convert any photo to grayscale. Files never leave your browser.

About Black & White · বিস্তারিত

Black & White converts a colour picture into grayscale, giving every pixel a shade of grey based on its brightness. It uses the Rec. 709 weighting (21% red, 72% green, 7% blue) so the result looks natural, and saves a PNG.

Simply averaging red, green and blue makes greens look too dark and blues too bright, because our eyes are far more sensitive to green. This tool uses the Rec. 709 luma formula, the same weighting used for HD video, so skies, skin and foliage keep believable tones.

The result is grayscale with smooth shades of grey, not a stark two-colour image. Transparent parts of the original stay transparent.

How to use it · কীভাবে ব্যবহার করবেন

  1. Choose a colour image

    Upload a photo, scan or graphic.

  2. Convert

    Press Run Black & White; there are no settings to adjust.

  3. Download

    Save the grayscale PNG, named with -bw at the end.

When it helps · কখন কাজে লাগে

Previewing a black-and-white print
See how a coloured chart, poster or photo will look before printing it on an office laser printer or photocopier.
Documents that ask for grayscale scans
Some offices and portals prefer grayscale copies of documents; a colour phone photo can be converted before submission.
A classic look for portraits
Old-style black-and-white portraits suit memorial posts, family albums and event pages.

What you get

  • Rec. 709 luma weights for natural grey tones
  • Smooth grayscale, not a harsh two-tone result
  • Transparency kept as it was
  • Same width and height as the original
  • Runs locally with no settings needed

বাংলায়: সাদাকালো ছবি

রঙিন ছবিকে এক ক্লিকে সাদাকালো (গ্রেস্কেল) করতে এই টুল। এটি মানুষের চোখ যেভাবে উজ্জ্বলতা দেখে সেভাবে হিসাব করে (Rec. 709 পদ্ধতি), তাই ছবিটা স্বাভাবিক দেখায়। অফিসের সাদাকালো প্রিন্টারে প্রিন্টের আগে কেমন দেখাবে বোঝা, বা পুরনো ধাঁচের পোর্ট্রেট বানানোর জন্য এটা কাজে লাগে। ফলাফল PNG, কাজ হয় ব্রাউজারেই।

এটা কি শুধু কালো আর সাদা, নাকি ধূসরও থাকে?

ধূসরের সব শেড থাকে, অর্থাৎ গ্রেস্কেল।

কোনো সেটিং বদলানো যায়?

না, এক ক্লিকেই কাজ হয়ে যায়।

Questions people ask · প্রশ্ন ও উত্তর

Is the result true black and white or grayscale?

Grayscale. Each pixel gets a grey level from 0 to 255 based on its brightness, so you see smooth shades rather than only pure black and pure white.

Why not just average the colours?

A plain average ignores how human eyes see brightness. The 0.2126 red, 0.7152 green and 0.0722 blue weights make bright green leaves look bright and deep blue skies look darker, as they do to us.

Will the file get smaller?

Not always. The PNG output is lossless, so a JPG photo can come out larger. Convert it to JPG afterwards if size matters.

Can I get a scanned-document look with pure black text?

This tool keeps grey tones. For a stark black-and-white trace of a drawing, the TIFF to SVG converter thresholds images at 50%.

Is the photo uploaded?

No. The colours are recalculated pixel by pixel in your browser, and the picture stays on your device.

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