When “In Spec” Still Looks Wrong: How Viracon’s Enhanced Delta E Collection Tightens Color Control on Neutral Glass

If you’ve ever stood across the street from a “neutral” glass façade and noticed 3 or 4 slightly different shades staring back at you, you already know the problem this article is about.

On paper, the glass is often in spec. In the field, it can read as a patchwork.

Viracon’s Enhanced Coating Delta E Collection is one way to close that gap—tightening color control so façades read as one coherent surface instead of a mix of panels that all technically pass ASTM, but don’t quite match your rendering.

This post walks through what that means, in plain language, and when it’s worth considering on your projects.

The Simple Question: How Consistent Will This Glass Actually Look?

Most conversations about glass focus on:

• U‑value and SHGC
• Visible light transmission
• Reflectance and glare
• Cost and lead time

All important. But there’s another question that usually surfaces later, often at mockup stage or after installation:

“Why doesn’t this all look the same?”

Viracon’s Enhanced Delta E Coating Collection exists to answer that question with a measurable, project‑level standard for color consistency—not just a coating target on paper.

Delta E in Plain Language (No Color Science Required)

You can spend a lot of time talking about CIELAB, L*a*b*, and color spaces. For most project teams, you don’t need to.

Here’s the simple version:

• Delta E (ΔE) is just a number that tells you how different two colors are from each other.
• The larger the number, the more likely you are to see a difference.
• ASTM C1376 says a Delta E of 4.0 or less for reflected color is “acceptable” for coated glass.

The catch:
On neutral, higher‑transission Low‑E coatings—the kind used on many modern commercial, institutional, and campus buildings—you can still see real variation at ΔE 4.0, especially across a big elevation.

So: “in spec” doesn’t always feel “right” to the client standing in the plaza.

Industry Standard vs. Viracon’s Enhanced Delta E Standard

Most of the industry still works to the ASTM C1376 tolerance:

• Industry norm: Reflected ΔE ≤ 4.0 across the project.

Viracon’s Enhanced Delta E Collection tightens that significantly:

• Viracon Enhanced Delta E: Project average reflected ΔE ≤ 2.0

That’s about half the typical tolerance.

In practical terms:

• You get far less visible variation across IGUs.
• Elevations read closer to the single, clean neutral you designed, instead of multiple “acceptable” shades.

Think of it as narrowing the window so what you see on the building actually looks like what you signed off on in the mockup and rendering.

How Viracon Does It: Per‑Project Color Control

This isn’t just a spec line—it’s a process:

1. Frequent test lites
   For projects choosing the Enhanced Delta E spec, Viracon runs test lites through the coater roughly every 30 minutes.
2. Objective measurement
   Each test lite is read with a spectrophotometer, logging ΔE values as the run progresses.
3. Scrapping out‑of‑band product
   If readings drift outside the tight color band, that glass is scrapped—it doesn’t make it into your project.
4. Project‑based acceptance, not just target‑based
   Your specification is tied to the average ΔE performance of the entire production run, not a single lab target.
5. Certificate of Acceptance (COA)
   At the end, you receive a project‑specific Certificate of Acceptance showing the ΔE distribution across your façade.

The net effect: there’s a measurable, traceable basis for saying, “This glass was produced and delivered to an average ΔE of 2.0 or less.”

Where It Actually Shows Up on the Building

Not every coating needs this level of control.

You notice color variation most on:

• Neutral, high‑transmission Low‑E coatings
• Elevations where glass is a major design element, not just an opening infill
• Projects with large, continuous façades and multiple viewing distances

In Martineau & Co’s work across the Northeast

1 3, that often means:

• Healthcare projects and campus work where neutral glass is a key part of the visual language
• Civic, institutional, and commercial buildings where the façade is an important public face of the organization
• High‑profile office, cultural, or convention projects where glass quality will be scrutinized up close

On those projects, an elevation that’s technically “in spec” at ΔE 4.0 can still read as multiple shades. Tightening to a 2.0 average keeps most variation in a range that people simply don’t notice in everyday viewing.

(For a broader look at the types of projects we support, you can always visit mandcomp.com and explore the project and partner examples there.

1 2)

Why Architects, Consultants, & Owners Should Care

Different stakeholders feel this in different ways:

Architects & façade consultants

• It’s about design intent: your “neutral” glass actually reads neutral and consistent.
• It means fewer awkward conversations when a client says, “This doesn’t match the rendering.”

Owners & campuses

• It’s about long‑term appearance and branding, especially for portfolios with multiple sites or phased construction.
• Future additions and adjacent projects have a better chance of feeling like they belong to the same visual family.

That doesn’t remove every disagreement, but it gives everyone something concrete to stand on.

When to Use Enhanced Delta E (Not Every Job)

Enhanced Delta E is a situational tool, not something to bolt onto every storefront or back‑of‑house elevation.

It tends to deliver the most value on:

• Signature façades and main entries
• Healthcare, campus, civic, and institutional work where neutral glass is front‑and‑center in the design
• High‑visibility, high‑expectation projects:
  • Science and research buildings
  • Hospitals and medical centers
  • Convention, cultural, and municipal projects
  • Prominent commercial towers or headquarters

In those contexts, the premium for tighter color control can be cheap insurance compared to the cost—financial and reputational—of a façade that looks subtly “off” for decades.

How It’s Specified (Without Writing a New Standard)

You don’t need to invent new language from scratch.

In the spec, it can be as straightforward as:

“Glass fabricator shall provide Viracon Enhanced Delta E Coating Collection with average reflected ΔE ≤ 2.0 to ASTM C1376, verified by Viracon’s Certificate of Acceptance (COA).”

Behind that single line lives:

• Per‑project measurement
• Active rejection of out‑of‑band glass
• A documented histogram of ΔE readings at the end of the run

You’re essentially anchoring your project to Viracon’s tighter internal standard instead of relying solely on the broader ASTM tolerance.

How Martineau & Co Helps You Use It Well

Locally, our role at Martineau & Co is to help you decide:

• When is Enhanced Delta E worth the premium?
• When is a standard spec perfectly fine?

We can help:

• Review your elevations, coating choices, and owner expectations
• Flag the facades where Enhanced Delta E would materially reduce risk
• Keep it off secondary areas where it may not add much value

Our project mix spans healthcare, education, civic and institutional, commercial, cultural, and more across the Boston–New York–Philadelphia corridor.

1 2. Enhanced Delta E is one of the tools we use selectively in that mix—not a one‑size‑fits‑all requirement.

Making It Real: Apply It to Your Work

If you’ve had a project where neutral glass didn’t look as consistent as you expected—or if you’re working on a new façade where appearance will be scrutinized—it might be worth a closer look.

If you share:

• An elevation,
• A proposed coating, and
• Any owner expectations around appearance,

we can come back with a quick recommendation on whether Viracon’s Enhanced Delta E Collection would genuinely reduce your risk or if your standard spec is already appropriate.

That’s what MCo Insights is for: taking tools like this out of the brochure and into the reality of the wide range of projects we support across the Northeast—so your façades look the way you intended, not just the way the numbers read on paper.