A postcard that looks like your business gets opened, read, and acted on. A generic-looking card gets recycled with the junk mail. PostKnock's design editor is built so you can customize every visible element — colors, logo, hero photo, copy — without needing a designer or any prior tool experience. This guide walks through each part of the editor in the order you'll use it.
Step 1: Set Up Your Brand Kit
The brand kit lives at Settings → Brand and stores the visual defaults every postcard pulls from. Setting it up once means every new design starts on-brand, so you don't have to re-pick colors and re-upload your logo every time. The brand kit covers four things: primary color, accent color, logo, and a default hero photo.
Color Palette
PostKnock uses two colors per design:
- Primary color — the dominant color on the card. Used for backgrounds, headlines, and the call-to-action button. Pick the color you'd describe as "your brand color" if asked.
- Accent color — used sparingly for highlights, the offer badge, and emphasis text. Should contrast with primary so it pops.
You can paste a hex code (e.g., #1E40AF) or use the visual color picker. PostKnock checks that text remains readable against your chosen colors and warns you if contrast falls below WCAG AA — helpful for postcards that will be read at arm's length by older patients.
Uploading Your Logo
Logo requirements:
- Format: PNG with transparent background or SVG. JPG works too if your logo has a solid background that matches the card.
- Resolution: at least 600×600 px for raster files. SVG scales infinitely and is preferred when available.
- Color: upload the version that reads well on a light background. PostKnock can invert your logo automatically when placed on a dark color block.
If the logo file looks pixelated in the preview, replace it with a higher-resolution version. Postcards are printed at 300 DPI, so a small logo file that looks fine on screen can look fuzzy in print.
Step 2: Choose a Template
Templates define the layout: where the hero photo, headline, offer, and contact block sit on the card. PostKnock ships templates organized by industry and by use case (recall, new patient, seasonal, sale). Each template comes pre-configured for all three postcard sizes (4×6, 6×9, 6×11), so you can switch sizes later without redoing the design.
When picking a template, consider:
- How much copy you have. A bullet-heavy template needs short, punchy bullets. A photo-forward template needs a great photo.
- Front vs back balance. Some templates put the offer big on the front; others reserve the front for branding and use the back for the offer detail.
- Photography vs illustration. Service businesses with strong office or staff photos do best with photo-forward templates. Brands without photos lean on illustration or color blocks.
Step 3: Add a Hero Photo
The hero photo is the single biggest visual element on most postcards. The best-performing hero photos for service businesses are photos of the actual office, the team, or the work being done — not stock photography. Stock photos are easy to spot and quietly tell the recipient "this isn't really from a local business."
Practical tips:
- Use horizontal photos with good lighting. Cell phone photos work fine if shot in natural light.
- Faces beat empty rooms. A photo of your dentist smiling outperforms a photo of your reception desk.
- Save the photo at 300 DPI or upload a high-res original. PostKnock down-samples; it can't restore detail that wasn't there.
Hero photos can be uploaded once into your media library and reused across multiple postcard designs. If you don't have a hero photo, the editor falls back to a clean color-block design that still looks professional.
Step 4: Edit the Copy
PostKnock's design editor breaks copy into specific fields, each with character limits tuned to the template and size. The fields you'll see for most templates:
- Headline (5–8 words). The biggest piece of text. "We Miss You, Sarah!" or "Time for Your Cooling Tune-Up."
- Offer (1 short line). The reason to act. "$50 off your next cleaning" or "Free system inspection."
- Bullets (3 short items, ~5 words each). Reasons to choose you, what's included, what's new.
- CTA (3–5 words). "Book your visit" or "Call today."
- Contact block. Phone, address, website. Filled automatically from your company setup.
- Disclaimer (small print). Offer expiration date, terms.
The editor enforces character limits in real time so the text never overflows the card or gets resized into something hard to read. If you need more room, switch to a larger postcard size (6×9 or 6×11) instead of cramming text into a 4×6.
Step 5: Preview and Proof
Below the editor you'll see a live preview of the front and back of the postcard. Personalization tokens (first name, custom offer code) are populated with sample values so you can see how a real card will look. Hit the "View at scale" toggle to see the postcard at its actual print size on your screen.
Before launch, PostKnock generates a Lob test proof — a digital rendering of the exact PDF that would be sent to print. This is the moment to walk away, come back tomorrow, and review with fresh eyes. Have a colleague look too. Print-quality issues are much cheaper to catch before you press launch than after 1,000 cards are at the printer.
Step 6: Save as a Reusable Design
Every customized design can be saved to your design library and reused on future campaigns. This is especially useful for multi-wave campaigns: you'll want a different design per wave (so cards don't look repetitive), but you'll want to reuse those same three designs every time you run the playbook. Your library keeps them organized and named.
Designs are kept separate from messaging. The same design can be used with different headlines and offers across campaigns — PostKnock treats visual design and message content as independent layers. For more on how the messaging side works across waves, see Multi-Wave Campaigns.
Common Design Mistakes
- Logo too small. A tiny logo defeats the purpose. The patient should recognize who sent it without reading.
- Too many fonts and colors. One primary, one accent, one font family. Restraint reads professional.
- Stock photos that don't match the brand. Better to use a clean color block than a generic stock image.
- Burying the offer. The offer should be visible at arm's length without reading every word.
- No call to action. Tell the recipient exactly what to do: call, scan, book.
If you're working on a recall card and want a deeper dive into the messaging side, our dental recall postcard guide has worked examples of headlines and offers that have proven effective.
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